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22 ATKINSON AND CARDIACOS ON I'apcr No. 5443. I' The Reconstruction of the Diyala Weir." By JOHN DEKEYNE ATKINSON, B.A., M. Inst. C.E., and GEORGE CARDIACOS, E.T.P. (Paris). (Ordered by the Council to be published .with written discussion.?) TABLE OF CONTENTS The rivcr and the sitc . . . . . . . . . . . . . . . . . 22 The original weir . . . . . . . . . . . . . . . . . . 24 The first reconstruction . . . . . . . . . . . . . . . . . 27 The 1937 repairs . . . . . . . . . . . . . . . . . . . 30 The final design . . . . . . . . . . . . . . . . . . . 32 The first season's work, 1939 . . . . . . . . . . . . . . . 36 The 193940 flood . . . . . . . . . . . . . . . . . . 38 The second season's work . . . . . . . . . . . . . . . . 38 Subsequent operation of the weir . . . . . . . . . . . . . . 41 The 1940-41 flood . . . . . . . . . . . . . . . . . . 41 Conclusions . . . . . . . . . . . . . : . . . . . . 43 Appendix: costs . . . . . . . . . . . . . . . . . . . 46 PAGE THE RIVER AND THE SITE. THE Diyala river rises in the mountain country on the Iran-Iraq boundary and flows in a south-westerly course to join the river Tigris 32.5 kilometres (20.2 miles) downstreamfromBaghdad. In the uppertwo-thirds of its course it passes through hilly country, emerging on to the Iraq plain at Table Mountain, a name given to this place in the Mesopotamian campaign during the last war, when the thirteenth and fourteenth Indian divisions were operating there and left memorials on two small hills on opposite sides of the river a short way above the site of the weir, which is 171 kilometres (106.25-miles)from the junction of the river with the Tigris. In 1917 a gauge, known as the Flying Bridge gauge, was erected at a site 1-428 kilometre (0.88 mile) above the weir, which has been regularly recorded ; a permanent flood discharge measuring station was established there in 1933, and is the only one of its kind on the river. There is another regularly recorded gauge a t Jalula, 38.5 kilometres (23.9 miles) above Table Mountain, The Alwan river, the last perennially contributing t Correspondence on this Paper can be accepted until the 16th March, 194G, and will be published in a Supplement to the Institution Journal for October l94fi. Con- tributions should be limited to about 600 words.-SEc. INST. C.E. ~~

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Page 1: J.D. Atkinson_Diyala Weir

22 ATKINSON AND CARDIACOS ON

I'apcr No. 5443.

I' The Reconstruction of the Diyala Weir."

By JOHN DEKEYNE ATKINSON, B.A., M. Inst. C.E., and GEORGE CARDIACOS, E.T.P. (Paris).

(Ordered by the Council to be published .with written discussion.?)

TABLE OF CONTENTS

The rivcr and the sitc . . . . . . . . . . . . . . . . . 22 The original weir . . . . . . . . . . . . . . . . . . 24 The first reconstruction . . . . . . . . . . . . . . . . . 27 The 1937 repairs . . . . . . . . . . . . . . . . . . . 30 The final design . . . . . . . . . . . . . . . . . . . 32 The first season's work, 1939 . . . . . . . . . . . . . . . 36 The 193940 flood . . . . . . . . . . . . . . . . . . 38 The second season's work . . . . . . . . . . . . . . . . 38 Subsequent operation of the weir . . . . . . . . . . . . . . 41 The 1940-41 flood . . . . . . . . . . . . . . . . . . 41 Conclusions . . . . . . . . . . . . . : . . . . . . 43 Appendix: costs . . . . . . . . . . . . . . . . . . . 46

PAGE

THE RIVER AND THE SITE.

THE Diyala river rises in the mountain country on the Iran-Iraq boundary and flows in a south-westerly course to join the river Tigris 32.5 kilometres (20.2 miles) downstream from Baghdad. In the upper two-thirds of its course it passes through hilly country, emerging on to the Iraq plain a t Table Mountain, a name given to this place in the Mesopotamian campaign during the last war, when the thirteenth and fourteenth Indian divisions were operating there and left memorials on two small hills on opposite sides of the river a short way above the site of the weir, which is 171 kilometres (106.25-miles) from the junction of the river with the Tigris.

In 1917 a gauge, known as the Flying Bridge gauge, was erected a t a site 1-428 kilometre (0.88 mile) above the weir, which has been regularly recorded ; a permanent flood discharge measuring station was established there in 1933, and is the only one of its kind on the river. There is another regularly recorded gauge a t Jalula, 38.5 kilometres (23.9 miles) above Table Mountain, The Alwan river, the last perennially contributing

t Correspondence on this Paper can be accepted until the 16th March, 194G, and will be published in a Supplement to the Institution Journal for October l94fi. Con- tributions should be limited to about 600 words.-SEc. INST. C.E.

~~

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TTIE RECONSTRUCTION OF THE DIYALA WEIR. 23

tributary to the Diyala, joins the main stream about 3 kilometres (2.86 miles) abovc Jalula (Fig. 1, Plate 1 ) .

Thc main river below Table Mountain flows in a well-defined chnwel through the alluvial plain and,.with the exception of the last 30 kilometres (18.6 miles), does not rise above the level of the plain in high flood. It is by nature a torrential stream in flood and is liable to very rapid rises and falls ; on 2 February, 1939, a rise of 3.97 metres (13 feet) was recorded a t Flying Bridge in 24 hours.

The main flood normally occurs in March, but peaks may occur a t any time during the months of January to May inclusive ; the normal low- stage period is from June to December. Fig. 2, Plate 1, shows the time- stage and time-discharge relations a t Flying Bridge and may be taken as representing average conditions ; the highest and lowest recorded gauges and the corresponding discharges are :-

Date. Flying Bridge Gauge. Estimated Dischurge.

3 February, 1939 metres.

3 July, 1932 70.50 * 65.24 t

cumecs. 3,080

1.5

Table Mountain is the name that was given to one height in the Gebel Hamrin, which is a long range of hills extending in a north-west-south-east direction across the northern part of Iraq ; it is pierced by three rivers, namely the Tigris at Fatha gorge, the Adhaim at Injana, and the Diyala a t Table Mountain, where the Gebel is composed of sandstone and con- glomerate containing some gypsum and is of little value for constructional purposes. The bed of the river here is gravel and sand, which occurs mixed, segregated, and layered, the former being mostly fine with a small proportion of larger gravel up to 4 inches and 5 inches.

The lands on both sides of the river are irrigated by a system of canals ; all those on the left bank take off in the immediate vicinity of the weir, but the head of the right bank canal, the Khalis, is about 5 kilometres (3.1 miles) upstream of the weir and outside its influence. The head of the Khalis was formerly just below the weir site, and the intention is to make a new offtake for the canal between the right flank of the weir and the hills, when the present head, which gives considerable trouble with gravel deposits in the head reach and requires the annual construction of a temporary bund in the river to ensure its water-supply, will be abandoned. Gravel deposits have also caused some trouble in the left bank canals, particularly the Ruz, which is the uppermost one. The layout of these canals is shown in Fig. 1, Plate 1.

The levels in the river during the low period were insufficient to supply the canals and .the discharge of the river a t this period is such that even

* After collapse of old weir and before reconstruction commenced. t While original weir was in operation.

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24 ATKINSON AND CARDIACOS ON

if all of it were diverted it would not meet the potential demands of the area for summer cultivation. Clearly then a weir had to be provided to divert the summer supply to the canals as the first stage in the improve- ment of summer irrigation, and a t some future period storage reservoirs will have to be provided farther up the river. Prior to the construction of the first weir a bund of brushwood and gravel was constructed each year by the local people after the flood had subsided, but this was destroyed by the first freshet of the following rainy season, which usually arrived a t the time of high water demand for winter sowings, which were thus often delayed, to the great loss of the cultivators.

This unsatisfactory state of affairs was first remedied in 1928 by the construction of a weir across the river just below the offtake of the Mahrut canal where the channel of the river broadens out very considerably.

THE ORIGINAL WEIR.

This consisted of a simple mass concrete core wall of trapezoidal form, with a crest-level of 66.00 metres (216.5 feet) ; the foundation-level was 63.00 metres (206.7 feet) throughout, whilst the bed of the river varied from 66.50 metres to 63.30 metres (218.1-207.7 feet). The main channel at that time was in the centre of the river ; it was about 100 metres (328 feet) wide and its average bed-level was about 63.4 metres (208 feet).

The original design included gravel filling on both sides of the wall, that on the upstream side having a slope of 4 : 1 and that on the down- stream 12 : l ; the former, however, was never made, but the latter was covered with a slab of reinforced concrete 0.10 metre (3.9 inches) thick divided by bitumen-filled joints into twelve sections, each measuring 36 metres by 36 metres (118 feet by 118 feet). The slab in each section was pierced by short lengths of 3-inch pipe, twenty to a section, to deal with upthrust. The length of the crest of this weir was 437 metres (1,434 feet), which is considerably more than the average width of the Diyala river ; the flanks were formed of concrete slabs laid on a 1 : 1 slope ; the layout and a cross-section of the weir are shown in Fig. 3. It was com- pleted on 24 September, 1928, a t a cost of ;E17,628, having taken 49 months to construct ; the quantities of work done were as follows :-

Excavation and filling . . . . 29,663 cubic metres (38,797 cubic yards) Mass concrete in main wall . . 2,765 ,, ,, (3,616 ,, ,, )

R.C. slab in D.S.' apron and flanks 18,018 square metres (21,549 square yards) Brickwork . . . . . . 145 ,, ,, ( 189 ,, ,, )

Good clean shingle and sand are obtainable in any quantities at the ,

site from the bed of the river. It was stated at the time of construction that the weir was to be con-

sidered as only a temporary structure, to be replaced by a more permanent one at a later date. After it,s construction a new gauge was erected just

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25

SECTION A-A. Scale 1 : 600

I

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26 ATKINRON AND CARDIAC08 ON

upstream from the weir on the right flank, which has been regularly recorded sincc 1929.

Although there was no cutoff on the upstream side, and 110 protective works at the downstream end of the apron, the weir functioned satis- factorily until 18 December, 1935, when it collapsed and was very largely destroyed. The river conditions preceding the collapse were that during November there were no violent fluctuations, the mean of the weir gauge for the month being 65.84 metres, that is, no water passing over the weir except on one or two days. There were rises of 0.46 metre and 0.41 metre on 1 and 2 December, or a total of 0.87 metre ; thereafter. it dropped back to 66-20 metres on the 17th, rising to 66.75 metres on the 18th, the day of the collapse, and to 66.95 metres the following day, after which it dropped right back again.

It had previously sustained more severe conditions than these without apparent damage, as may be seen from the following Table of maximum flood levels since the time of construction :-

Year.

1929 . . 1930 . . 1931 . . 1932 . . 1933 . . 1934 . . 1935 . .

Weir Gauge. metres 66.64

feet

67.30 218.58

66.62 220.74

66.78 218.51

67.14 21944

66.99 220.22

66.95 '

219.73 219430

This seven-ycar period was one of low floods, whilst the following seven- year period was one of high floods ; the mean maxima, a t Flying Bridge gauge, for the two periods were 67.50 metres (221.46 feet) and 69.26 metres (227.23 feet) respectively. For four out of the seven years of the latter period the weir was breached and therefore levels at the weir gauge are not comparable.

At the time of the accident it appears that there was a standing wave on the downstream slope at or a little below the mid-point, and an eye- witness saw a slab lift and turn over about 160 metres (525 feet) from the left bank and about half-way down the slope, but above the standing wave and therefore at the part where the depth of water on the slope was least. The hole spread quickly on both sides and worked back to the wall, but this did not collapse until the whole of the upper portion of the slab had disappeared and the water was falling vertically over the wall, pre- sumably undermining it and causing its eventual collapse. The main flood which followed during the early part of 1936 increased the damage and caused further scour around the fragments, which settled deeper and broke up into smaller pieces ; the extent of the damage is well indicated in Pig. 4, which shows the gap in the concrete wall, t.he undamaged section, and the paved slope on the right bank.

Page 6: J.D. Atkinson_Diyala Weir

Fip. $.

Page 7: J.D. Atkinson_Diyala Weir

Fig. 13.

i COMMENCEDTENT OY 1040 SEASOK’S WORK-UPPERLINE OF PILES AND STEPPED

CONCRETE on 1939 SEASOS’S W O R K AFTER PASSAGE OF 193940 FLOOD.

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THE RECONSTRUCTION OF THE DIYALA WEIR. 27

Examination of the slab over the sections which were apparently undamaged revealed that it had bulged upwards in two places in the left bank section over an area of 2-3 metres (6.6-9.8 feet) diameter and as much as 20 centimetres (7.87 inches) in height at the larger bulge, which was that situated nearer the breach. When the larger bulge was later removed for repair it was found that a gap existed between the underside of the slab and the gravel filling but the latter was apparently all in place and undisturbed ; the slab itself was cracked a t both bulges.

These facts would seem to point to uplift under the slab about half-way down the slope as the primary cause of the disaster, and as the concrete when examined was found to be of good quality, lack of strength was not considered as a possible contributory cause of the collapse.

When the floods had finally subsided and the river had dropped suffi- ciently for a more detailed examination of the damage to be made, the situation was found to be as follows, the distances being from the right flank :-

metres feet 0-77 0-252 No apparent damage. . Toe of weir covered with gravel

so that only the upper half of the downstream slope was visible.

77-114 l l P 2 2 0

252-374 Wall not damaged, but all the slope gone. 374-722 Breach in the crest wall of 106 metres (348 feet) in length

in which all the slope had gone, whilst the wall had broken up into sections the longest of which was about 10 metres (33 feet). The pieces had sunk 2-3 metres (6.6-9.8 feet) below the original wall levcl and had

about 15 metres (49 feet) in which the fragments of moved slightly downstream. There was one gap of

the wall were not visible and their position was uncer- tain; they were believed to have sunk deeply and to have been covered with silt deposited by the.falling flood.

220-307 722-1,007 Wall standing but slope all gone ; the wall was cracked

about 3 millimetres (0.12 inch) wide. in two places but had not settled-the cracks were

307-351 1,007-1,152 Parts of the slope still in place, but all badly cracked and

351437 1,152-1,434 Slope nowhere removed, but many serious cracks, slight crumpled with cavities underneath.

the surface. lifting along the lines of 'some cracks, and bulges in

Fig. 5 shows the undamaged left flank after the flood had subsided.

THE FIRST RECONSTRUCTION

Steps were immediately taken to repair the weir during the summer of 1936. This time it was proposed to substitute sheet-steel piling for the portion of the crest wall that had collapsed and t o add a similar line of shorter piles at the toe of the slope, the paved slope on the downstream side being replaced in the six damaged sections by a new slab of 0.15 metre (5.9 inches) thick, reinforced as before, and it was decided not to do any-

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28 ATKINSON AND CARDIACOS ON

Fig. G.

4 cm. thick 20 m. apar SECTION A . A

. * Scale l : 600

R.L. 63.00 D.$.

Steel sheer pier 10 m. long steel sheet piles 5 m. long 36.0 m----.

-- DETAIL OF REINFORCED CONCRETE SLAB Scale 1: 60

Reinforced concrete slab 1.2: 4 15 cm. thick

Scale 20 . , , 40 . 80 , 140 , 160, Zoomerrer

FIRST RECONSTRUCTION IN 1936.

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THE RECONSTRUCTION OF THE DTYALA WRTR. 29

thing to the undamaged portions at the ends of the weir, as they appeared generally to be in good order ; however, the larger of the two bulges on the left bank was cut out and the slab was re-made. Pig. 6 shows the type adopted for the reconstruction. The sheet-pile chosen for this work was of a very heavy and stiff section, namely, " Ougr&e " No. 4.S., details of which are given in Fig. 7.

The work was put in hand in the summer of 1936, but an early flood arrived on 4 December before the new slab below the piles had been com- pleted. At the time of the accident the state of the work appears to have been that the lower line of new piles 5 metres (16.4 feet) in length had been completed and driven to level, and the 10-metre (32-8-foot) piles of the

Fig. 7.

' 5 . SHAPED0UGREE"PILING No. IV SECTION WITH EXTENDED CLUTCHES OF 151 M l M

Scale 1:15 AII dimensions in millimetres.

TYPE OB SHEET-PILING USED IN FIRST RECONSTRUCTION.

upper line had all been pitched ; but of the total of 229 piles in this line only 192 had been driven to full depth or to refusal ; the driving of the remainder was actually in hand when the flood arrived, but was not com- pleted until some time later. The tops of the piles that had not reached full depth were cut off, the length removed ranging from a few centimetres to 3.85 metres (12.62 feet). The slab covering the filling on the down- stream side had been completed with the exception of a small section about 36 metres (118 feet) long at the top of the slope opposite the piles remaining to be driven, which had been left in order to provide a working base for the pile-frame.

The hard ground into which the piles could not penetrate was found nearest the surface from Nos. 164 to 229 on a length of about 62 metres (203 feet). A trial pit and probings made opposite this section near the

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30 ATKTNRON AND CARDIACOS ON

lower line of piles proved the existence of what was described as soft rock under the bed of the river a t t hk place, the surface of which was found to be at about level 60 metres (197 feet) at the highest point.

The conditions in the river immediately preceding and following the accident were that the river started rising at the end of November ; on the morning of 3 December the weir gauge recorded 66.23 metres (217.29 feet), rising to 66.68 metres (218.8 feet on 4 December, and to 67.13 metres (220.19 feet) on 5 December, after which it fell and remained almost steady a t 66.30 metres (217.53 feet) for the rest of the month.

The sequence of events appears to have been that the water passing into the unprotected section where the pile-frame was located speedily removed the filling and undermined the slab, lifting it completely over ; the process extended until more than half of the new slab had been destroyed, and the pile frame eventually fell over into the hole created.

THE 1937 REPAIRS. Further repairs were undertaken in the summer of 1937. Examination

of the lines of piling already driven showed them to be intact and appar- ently sound, and it was therefore decided to box in the piled section by constructing cross walls a t each end and two other similar walls equally spaced in between, and further to sub-divide these boxes by another wall parallel to the lines of piles and 15 metres (49 feet) below the upper line, thus dividing this section into six more or less equal rectangular compart- ments. At the same time the two lines of piles were to be completed right across the river as a further protection to the as yet undamaged portions of the original weir. These proposals were, however, never completed, owing to lack of credits and delay in obtaining the

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THE RECONSTRUCTION OF THE DIYALA WEIR. 31

During the remainder of the month levels were low, except on the 28th, when the river rose to 68.40 metres (224.41 feet) a t Plying Bridge.

It will be noticed that on the evening of the 9th there was a depth of 2 metres (6.56 feet) of water over the crest of the weir, and it was this spate that caused the initial damage, of which there was no actual witness.

The weir was examined on 2 June, when the floods had subsided and its condition was that, with the exception of a short length at the extreme end on the left bank, all that had remained of the original weir before the arrival of this flood had been destroyed, some damage had been done to the protection to the slope of the right bank, and the central section of the new intermediate wall between the lines of piles had also been removed, but no damage appeared to have been caused to either of the two lines of piles.

After this collapse it was proposed to complete the work to the 1937 design, but, following on the report of a committee charged to examine the matter, the Ministry of Communications and Works decided that an independent opinion on the proposed design should be sought, with the result that, on the basis of the information supplied, a type was proposed which differed very materially from all previously proposed types.

The remaining period of the 1938 season was insufficient to allow of any work being done that year, but calls for tenders were made with a view to starting work as early in 1939 ae river conditions would allow, and offers were received in January 1939.

At this stage the first Author was appointed Chief Engineer of the Irrigation Department, and shortly after he took up duty the project was turned over to him for decision as to whether work should be proceeded with in the coming season or not ; the second Author joined the Depart- ment in the following May, as Chief of the Hydraulic Section.

On making an examination of the project, five points affecting the design appeared to require further study :-

(l) It was very desirable to bring the head of the Khalis canal back to its original site and into the influence of the weir, thus avoiding the annual construction of a temporary bund in the river at the existing head. This raised the question as to what level would be required in the new channel to command the land served by the Khalis, and accordingly a survey and levelling were made and contours were examined. These showed that a maximum of 66.10 metres (216.86 feet) on the downstream side of a new regulator sited close to the weir would give the required command. It therefore appeared that the crest of the weir should be raised 0.50 metre (19.68 inch) to a level of 66.50 metres (218.18 feet), which would also give ample command for the left bank canals.

(2) The very restricted working season, and uncertainty as to the date when conditions would permit .work to start and of arrival of the first flood, made it very probable that the work could not be completed in one season. In this case, how should the work be divided over two seasons

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32 ATKINSON AND CARDIA008 ON

and in what state should the first season’s work be left so that it would be reasonably secure against damage from the flood T

(3) The two lines of piles already driven, particularly the line of 10-metre (32.8-foot) piles, were badly aligned, being as much as 2.5 metres (8.2 feet) away from the straight line between the two ends.

(4) There were two main channels in the river, one a t each end of the existing line of piles, whilst the river-bed beyond the lower line was for the most part high, up to 65.0 metres (213-25 feet), with irregular gaps through which the water escaped. This had resulted in cross currents more or less parallel to the axis of the weir and along the line of the lower line of piles and indicated that it might be desirable to raise the dividing walls above the apron-level to form guide walls and lead the water off the apron in the desired direction.

(5) It seemed that some more positive protection against scour at the toe of the weir than that provided by the last line of piles was desirable, in view of the torrential nature of this river.

These considerations led to the reconsideration of the design, but before proceeding with this the site was carefully examined to see if the old location of the weir was the best from all points of view. This was found to be the case, and accordingly the piling’ already driven could be incorporated in the design if on examination it was found to be sound and intact. The records of the driving and the reports of the engineers who were there at the time were studied and a careful inspection was made on the site, with the result that nothing was revealed to indicate that they could not be incorporated in the new work with perfect safety. Fig. 8 shows the upper line of piling as it then was. It was then definitely decided that the crest-level should be 66.50 metres (218.18 feet) ; that the work should be done in two seasons ; that the existing lines of piles should form a part of the new work ; and that all the remaining concrete of the original wall should be removed, as the foundation-level of the old wall was 1.0 metre (3.28 feet) above that adopted in the new design.

THE FINAL DESIGN. The outline chosen is shown in Figs. 9. The crest wall is of a type

with good discharging properties which had been tested in Egypt and of which the properties were known ; the upstream face is vertical, rounded to 0.50 metre (1.64 foot) radius a t the top, followed by a horizontal section 0-50 metre wide, at the end of which commences a 3 : 1 slope, 3 metres (9.84 feet) long ; the paved apron starts from here on a l2g : 1 slope, finish- ing with a horizontal section of paving, at the end of which was placed a scour-preventing lip wall 1, as described in 1932 by Messrs. A. D. D. Butcher and J. D. Atkinson.1

‘‘ The Causes and Prevention of Bed Erosion, with Special Reference to the Protection of Structures Controlling Rivers and Canals ”, Min. Proc. Inst. C.E., vol. 236 (1932-33, Part I), p. 219,

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THE HECONSTRUCTION OF THE DIYALA WEIR. 33

The weir wall is of mass concrete between two lines of sheet-steel pile$ placed 3 metres (9.8 feet) apart, the upper line being 10 metres (32-8 feet)

’ long, with its top level a t 66 metres (216.5 feet) and the lower 5 metres (16.4 feet) long with its top level a t 63 metres (206.7 feet), the foundation- level of the concrete being 62 metres (203.4 feet) throughout.

The major problem was th: design of the first season’s work, and it was thought that the type most likely to stand up to the effect of the flood would be a stepped weir with the top step well below the top of the uppcr line of pilcs and the lowest step below the top of the lower line.

Fig. 9.

(4 66-00 Portion of dividing wall reason 1939

Bed of river average ..:. %-<7.i .._. ‘...::;.,~.~~~.-.-.~...-.~~. ip.

3rd row of pller I s t row of piles .., Yb!

5 p - - 37.00 varying ’I

Scale 1:600

SECTION ON WEIR, FIRST SEASON’S WORK, 1939.

1.0 3.00

Bed er

Scale l: 600 FINAL SECTION OB- WEIR, SECOND SEASON’S WORK, 1940.

The considerations that led to this design were : (a) the water should not drop abruptly from the lower line, as this would inevitably cause heavy scour below ; (b ) an abrupt drop at the upper line on to successive steps would break up the jet and help to destroy its energy ; (c ) the projection of the lower line above the lowest step would throw the lower layers of the water clear of the piles and induce a return vortex behind them which would prevent erosion in their immediate vicinity. The idea was tested out on a model and the results were so encouraging that it was decided to go straight ahead on these lines (Figs. 9).

The sheet-piling necessary to complete both of the existing lines and also for the new line was immediately ordered and the remainder of the first season’s work, comprising the driving of the piles, the removal of the

3

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34 ATKINSON AND CARDIACOS ON

old concrete, the new concrete steps, and the first 10 metres (32.8 feet) of the dividing walls, which should act as guides, was put to adjudication.

At the same time the proposed final type of the weir was tested on models, with particular reference to (a) the position of the standing wave, which was found to be well on the paved slope throughout the range ; ( b ) erosion at the toe, from which was determined the most effective position of the lip wall ; and (c ) the discharge formula, in order to check the height of the water a t estimated maximum conditions of flow and thus obtain the height of the abutments which it was proposed to construct in place of the existing paved slopes on the flanks.

It will be seen from Fig. 10, Plate 2, that the length of the finished weir between abutments is 409.6 metres (1,344 feet), whereas that of the original weir was 437 metres (1,434 feet) ; this shortening was decided upon in order to give sufficient room for the new head of the Khalis canal on the right bank, but, as the time available for the work in the first season was insufficient to allow of undertaking the construction of a new abutment on this bank, the lines of piles were completed for the full 437 metres and tied into the existing paved slopes at the extremities of the old weir. The piling, which extends beyond the right abutment as now constructed, will be tied into the masonry of the new Khalis regulator.

The inclusion of the existing lines of piles driven to certain levels and not in good alignment imposed some restrictions on the design and created some difficulties. The first of these was that it was not possible to make the crest wall one straight line from end to end ; it is in three parallel lines, the centre being the farthest upstream, whilst that towards the right bank is set back 2.3 metres (7.5 feet) and that towards the left bank 1.40 metre (4.6 feet), and the three lines so formed are joined together by I

short sections inclined back a t a horizontal angle of about 6 degrees (actually tan 0.1). The slightly staggered effect produced is not un- pleasing in a structure of this length. Another difficulty arose from the fact t,hat, whilst the piling generally fell into the lines mentioned, there were local irregularities in each line such that the thickness of the concrete outside the upper line of piles was variable apart from the variation due to the corrugations of the piles themselves ; this latter variation was constant and was 0.51 metre (20 inches) ; the former varied from 0.10 metre (3.94 inches) to 0.90 metre (35.4 inches), so that the thickness of the outer concrete varied from 0.10 rnctre to 1.41 metre (462 feet). Furthermore, if this concrete had been carried down and founded on the bed of the river it.s height would have been very variable following the contour of the river sect,ion. Therefore it was decided to cut off this concrete at level 64 metres (210 feet), and where the bed was below this to dump gravel in front to bring the bed up to this level (Pig. 9) ; it was anticipated that the river itself would fill up the corner between the dumped material and the weir with natural deposit, and that was what happened, as the bed of the river contiguous to the concrete was found, in the summer of 1941, to be nowhere

Page 16: J.D. Atkinson_Diyala Weir

THE RECONSTRUCTION O F THE DIYALA \IrEIR.

W

Y

U

F 9

Y J

Page 17: J.D. Atkinson_Diyala Weir

36 ATKINRON AND OARDIACOS OK

below level 65 metres (213.25 feet) ; the deposit was very fine silt. It was also decided to insert stirrup reinforcement in the concrete a t each of the pile corrugations and to reinforce the vertical face of the weir with B.R.C. No. 14, or similar fabric, where the thickness of the concrete was less than 0.20 metre (7.87 inches). Details of these reinforcements are shown in Fig. 11. Otherwise the design calls for no particular comment.

THE FIRST SEASON’S -WORK, 1939.

The items comprised in this season’s work were-(l) Construction of the temporary sudds ; (2) construction of housing ; (3) excavation and filling ; (4) demolition of old concrete ; ( 5 ) driving the piles supplied by the Department ; (6) concreting the main and dividing walls ; (7) partial

Fig. 12.

Right ban R.L. 69.00

Ground level t 66.00

\

z SKETCH P L A N SHOWING ISOLATING SUDDS DURING 1939 SEASON’S WORK.

demolition of the slabs on the slopes at the flanks and repaving with pre- cast blocks. This was put out to contract with a completion period of four months starting from 24 June. Work actually started at the beginning of July and was fully completed by 14 November.

During this period river conditions were favourable for the work ; no appreciable rise occurred until 20 November, and the whole of the river discharge was taken into the canals once the mdds (Fig. 12) had been completed. These sudds were made of the material available a t the site, which was mostly gravelly sand, and they gave some trouble with breaches at the beginning and with leakage throughout the period of the work, which involved a considerable amount of pumping. No serious difficulties

Page 18: J.D. Atkinson_Diyala Weir

THE RECONSTRUCTION OF THE DIYALA WEIR. 37

were encountered other than in keeping to the timetable in view of the shortness of the working season.

Small charges of explosive were used for breaking up some of the mass concrete of the old wall where it was visible and could be got at, but in t,he course of the pile driving towards the left bank the line had to be diverted slightly to avoid odd blocks of the old concrete which had dug themselves too deeply into the bed of the main channel on this side, which was the deepest part of the river. Their position and size were ascertained by careful probings, and their tops were found to be a t about foundation- level, with the bottom well above the foot of the piles. When the founda- tions were later uncovered they were found to be very firmly embedded. Any attempt to remove them would have been a matter of great difficulty and would have held up the work, and if it had bcen successfully accom- plished there was no guarantee that other unlocated pieces did not exist. No evidence was available from the driving or the subsequent cxaminat,ion of' the exposed foundations to show that the ground was any different or less compac,t in their immediate vicinity than elsewhere on this side of the river. Further, it was considered that the presence of the one located piece inside the closed box formed by the two lines of piles and closed by the concrete'cap of the main wall was unlikely to affect the stability of the weir, and it was accordingly left in place.

On the left bank a line of 10-metre piles, 43.70 metres (143.4 feet) long was driven a t right angles to the axis of the weir, tying the main line to the wing wall of the Mahrut canal regulator ; the top of this line was at level 69 metres (226 feet).

During the course of the work it was decided to tie the second line of piles to the stepped concrete of the main wall, as it was feared that the impact of a large volume of water falling off the steps against the projecting portion of the piles would be of considerable magnitude and liable to start them vibrating, which would tend to separate them from the concrete and might damage the lower step, which was only 0.50 metre (164 foot) thick. For this purpose l-inch hook bars, 1 metre (3.28 feet) long, were set in the concrete a t mid-depth of the lowest step, with the threaded end projecting through holes drilled in the pile, the nuts being tightened up after the con- crete had set. These hooks were put in a t every fourth pile.

While the steps were being constructed suitable pieces of the old con- crete were set in each step for the double purpose of breaking up the jet of water and providing keys for the next season's concrete ; suitable pieces of cuttings from the piles were also inserted for the same purpose after cleaning, and these inserts are clearly visible in Fig. 13.

The upper portions of the new dividing walls, seven in number, were also successfully completed, although some trouble was experienced in getting the foundations dry in those on the right side of the river.

Mention may be made of a peculiarity in the nature of the foundations on the right bank where the free water surface on the upstream side was

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3.8 ATKINSON AND CARDIACOS ON

farthest away from the weir owing to the presence of an extensive and high deposit in the river (Pig. l a ) , the seepage was greatest and came from numerous very small springs. The usual manner of dealing with such springs was unsuccessful and, finally the concrete in certain sections had to be laid by tremie methods after allowing the water to rise, which it did to a depth of about 0.30 metre (11.8 inches), and satisfactory results were obtained. The same method had to be employed in the foundations of the first three divide walls on the right bank. In contrast to this, as the main channel was approached, with the water standing against the piles and 2.5 metres (8.2 feet) above the bottom of the foundations, springs had completely disappeared and the small quantity of seepage water was kept down with one pump.

THE 1939-40 FLOOD. After completion of the wofk no notable flood occurred until the end

of January, 1940, but from this time on until the end of Pebruary the work was severely tested, particularly by the great flood of 22 February, when the level upstream of the weir rose to 68.20 metres (2234’5 feet), that is, 2.20 metres (7.22 feet) depth of water over the top of the piles ; only once before had such a flood been recorded. The rise was very rapid and high levels persisted for several days, the recorded levels being :-

Weir Gauge. metres

February 21 . . . . I 66.63 ,, 22 . . . . 68.20 ,, 23 . . . . 67.20 ,, 24 . . . . 66.90 ,, 25 . . . . 67.03 ,, 26 . . . . 67.65 ,, 27 . . . . 67.45 ,, 28 . . . . 67.07 ,, 29 . . . . 66.90

feet 218.55 223.70 220.47 219.43 219.86 221.89

220.00 221.24

219.43

THE SECOND SEASON’S WORK. Offers for the completion of the work were called for in February and

a contract was placed in the following month, although work on the weir itself could not commence until July, when the water had subsided ; this was done in order to give the contractor ample time to make the blocks, of which 18,200, of dimensions 1.50 metre by 0.50 metre by 0.40 metre (4.9 feet by 19.7 inches by 15.75 inches) were required for paving the apron of the weir and 2,920 of dimensions 0.40 metre by 0.40 metre by 0.20 metre (15.75 inches by 154’5 inches by 7.87 inches) for pitching the side slopes by the abutments ; block-making started in April.

As soon as river-levels permitted, a careful examination of the previous season’s work was made. No damage or displacement was discovered

Page 20: J.D. Atkinson_Diyala Weir

Fig. 14.

FOUNDATION Coh-cnem POR TRE RTWT ABUTMENT AND PITCIIED SLOPE, AND PART OF FlNlSXED CREST OF NEW WmR.

Fig. 16.

THE IIom AND UISPLACED BLOCKS IN BAY AND AFTER TIIE 1940 FLOOD.

Page 21: J.D. Atkinson_Diyala Weir

Fig. 19.

Page 22: J.D. Atkinson_Diyala Weir

THE RECONSTRUCTION O F THE DIYSLA WEIR. 39

and i t had resisted the battering it had been subjected to in a highly satis- factory manner, whilst no serious erosion had occurred on the downstream side of the second line of piles where trouble might have been expected ; the correctness of the model experiments was thus confirmed. A natural effect, due to the flow of the river having been evenly distributed over the whole width instead of having been concentrated into two channels, as was the case prior to the first season’s work, was a general levelling up of the river-bed below the second line of piles and more particularly between the second and third lines, which resulted in a decrease in the quantity of excavation required and an increase in that of filling. The two old main channels had filled up appreciably, particularly that on the right

Fig. 15.

SKETCH PLAN SEOWING ISOLATINO 8UDDS DIJRINC 1940 SEASON’S WORK.

. bank. The third line of piles had been completely buried by this same levelling process, which had also exposed a great deal more of the old reinforced slab paving than had been believed to exist, and all of this had to be broken up and removed in order to expose any cavities that might have existed and have subsequently caused local settlement of the new block apron if not filled.

Richlier mixers of 64 cubic feet capacity were used for making the blocks, which were cast in stout wooden moulds suitably braced. Two lifting irons were inset into each stretcher and one in each header. Tho best weekly output of blocks was 1,554.

At the beginning of July the construction of the isolating sudds was started,which was arranged to divide the work into three sections (Pig. 15). The two ends of the weir were sudded off first and concreting of the main wall was started from both ends whilst at the same time a start was made

Page 23: J.D. Atkinson_Diyala Weir

40 ATKINSON AND CARDIACOS ON

with the foundations of the abutments. In this season, as in the last, dificulties were encountered in the foundations on the right bank and again tremie methods of placing in the abutment had to be adopted. No difficulty was met with on the left bank. This trouble was accentuated in the foundation of the small concrete wall at the foot of the pitched slope on the upstream side of the right abutment, which was eventually put in at level 61.50 metres (201.77 feet) instead of 61 metres (200.16 feet) as originally designed. This pitching showed no sign of movement subse- quently and the lower part of it has been covered by natural deposit ; it will be demolished and removed when the new head regulator of the Khalis canal is built (Pig. 14) .

Gravel and sand for all concrete was obtained, as in the previous season, from the bed of the river in the immediate vicinity of the weir, and in all classes of concrete were used in dry proportions, that is, as taken from the stock piles, of l cubic metre (1.3 cubic yard) of gravel to 0-5 cubic metre (0.65 cubic yard) of sand with various quantities of cement as follows :-Class A , in the mass concrete of the main weir, divide walls, and foundations of the pitched slope, 250 kilograms (650 lb.). Class B, in all blocks, the abutments and steps for the gauges, 300 kilograms (660 lb.). Class C, for the special concrete on the crest of the weir and the reinforced lip wall, 350 kilograms (770 lb.). The specification allowed for variation in the quantity of sand in the mix, and was adjusted from time to time, producing dense concrete which gave very satisfactory results on test.

Metallic forms were used for casting the curved portion of the crest, whilst the other exposed surfaces of it were worked with floats and by trowelling produced a good even and dense skin. The main wall was concreted in alternate sections of about 3 metres (9-84 feet) in length.

In view of the fact that the upstream face of the solid weir will always be in contact with water, and will therefore be maintained a t a fairly con- stant temperature, whereas the crest and the 3 : 1 slope are exposed to extremes of temperature, expansion joints were introduced a t intervals of 9--10 metres (29.5-30.8 feet) from end to end and arranged to fall cen- trally hetween two reinforcing stirrups. Similar joints were made in the dividing walls and in the lip wall at its junction with each of the former.

The left abutment bestrides the first line of sheet-piling and the right abutment bestrides both the first and second lines. The foundation-level of the abutments is 62 metres (203-4 feet) and the tops of the fist and second lines of piles are 66 metres (216.52 feet) and 63 metres (206.69 feet) respectively; the second line thus penetrates the concrete 1 metre (3.28 feet), but the first line splits the abutment for more than half its height into two unequal portions tied together only by the concrete of the retain- ing wall above pile-level. Any settlement on either side of the pile would in all probability produce an unsightly crack in the exposed face of the abtltment running up from the pile, and to avoid this a joint was made

Page 24: J.D. Atkinson_Diyala Weir

THE RECONSTRUCTION OF THE DIYALA WEIR. 41

in each retaining wall located at the line of the upper piles ; each abutment thus consists of two independent sections.

After forming the 1 : 12g slope it was compacted with a 4-ton diesel roller and on the finished surface was laid a 0.35-metre (13.78-inch) layer of screened gravel graded to pass a 6-centimetre (2.36-inch) ring and not passing a 2-centimetre (0.79-inch) sieve.

Very few header blocks were pre-cast, as it was realized that there would be difficulty in laying them on the selected gravel filling without creating cavities under adjoining stretcher blocks and that a better result would probably be obtained by casting the headers in place, which proved to be the case. Four lines of headers were cast right across the weir, spaced a t even intervals up the apron; they were cast alternately in lengths of 1.50 metre (4.9 feet) corresponding in length with the stretchers and breaking joint with them and were separated from each other and from the stretchers by greased paper joints. All other make-up cast-in-situ blocks at the end of the lines of stretchers and at the top of the paved slope were similarly separated from neighbouring blocks and the abutting concrete walls.

The work was completed and taken over on 7 November; the hand- railings on the abutments were not included in the main contract, but were added in the summer of 1941. The quantities of the various classes of work done, together with the cost, are shown in the Appendix.

SUBSEQUENT OPERATION OF THE WEIR. It was anticipated that some localized settlement or displacement in

the blockwork of the apron would occur in the first two or three years of operation, and that it might be necessary to replace some of the blocks. Accordingly a small reserve of blocks was accumulated a t a convenient site on the right bank clove to the weir.

THE 1940-41 FLOOD. Water first passed over the weir on 13 November, just a week after

the completion of the work, and an inspection shortly after showed a very smooth and even flow over the crest and apron, with the exception of two places where there was evidence of either slight settlement or irregularity in the setting of one or two blocks. There was no flood of any note until 10 February, when the mainflood arrived, and the river rose to a maximum of 68.12 metres (223.49 feet) on the next day, corresponding to a discharge of 1,688 cumecs, having risen 1 metre in the previous 24 hours, and there- after remained above level 67 metres (219.32 feet) until 7 May ; flow over the weir ceased at the end of June.

Some time before the weir became dry it had been noticed that there was a hole in the apron in bay No. TV, about half-way clown the slope, and

Page 25: J.D. Atkinson_Diyala Weir

42 ATKINSON AND CARDIACOS O F

that a number of blocks had been completely removed, whilst there hamcl also h e n some displacc~nent of individual blocks in bays V and VIII.

When the weir becanle dry a careful examination was made of the whole structure, which, with the exception of the displaced blocks, was found to be in perfect order, although, as already recorded, silfing had taken pla.ce all along the upstream face. The irregular hole in bay IV, from which some blocks had been entirely removed, was 13 metres (42.65 feet) long and 10 metres (32.81 feet) wide, greatest dimensions, which would correspond to something less than 100 blocks. The blocks had been rolled along the apron, fetching up at the lip wall where they were piled together in an irregular manner, whilst one or two had even surmounted the wall. All were intact and had suffered nothing worse than some slight abrasion a t the angles. The filling had been removed to a depth of about 1 metre and in the hole so formed several blocks were found embedded in the filling, which were subsequently recovered and replaced in position. The blockwork around the hole had subsided in greater or lesser degree, but this subsidence did not extend far from the perimeter of the hole (Pig. 16). There was also a small hole in the centre of bay V from which three or four blocks had been removed, and several had sunk and others had been lifted in bay VIII, but none had been removed. It was observed that where a block had sunk below the general level the block immediately below i t had been lifted above the general level to as much as one-third of its depth, and in nearly every case the lift was greater at the leading edge. In this bay the process of lifting appeared to have been stopped by the blocks eventually becoming jammed, and in this connexion it may be noted that, although care was taken while laying them to make the joint as small as possible, it was difficult in practice to avoid an occasional joint wider than desirable ; several such were noted during the final inspection on taking over the work, and these were packed with fine' gravel.

If the evidence is correctly interpreted, it emphasizes the importance of laying such paving blocks in the closest contact, with even joints, which implies care in the moulding to obtain flat sides, and of avoiding any projections above the general surface of the apron. In making the repairs to the damaged bays the former of these could not have been ensured without relaying the whole bay and casting new headers and makeups. However, it was possible, while relaying the damaged portions, to see that '

the leading edges nowhere protruded above the trailing edges of the blocks immediately above. This was done, and the subsequent freedom from serious movement of the relaid blocks appears to confirm the deduction that the projection of a block above the general level leads to its being lifted,provided that the joint is wide enough for the water to act and move- ment to take place.

It was also observed that in several places, where a block had either been laid slightly protruding or had been lifted by the action of the water

Page 26: J.D. Atkinson_Diyala Weir

and subsequently jammed, the protruding edge, on the leading side only, had been worn away and smoothed off. This effect was noticed only in the upper part of the weir and was attributed to the battering effect of the gravel carried over the weir a t a high velocity against the obstruction. Pig. l 7 shows a pile of gravel and sand accumulated on the apron by the flood of 1943 and illustrates the nature and size of the transported material.

After the flow had ceased the river-bed below the weir became per- fectly dry and remained so throughout the summer. Some water was left standing in the lower part of bays I and 11, which gradually evaporated and disappeared, but apart from this the only sign of water below the crest was very slight leakage through three or four of the expansion joints of the solid weir,

CONCLUSIONS.

The observations of the movement of the apron blocks during the three years during which the weir has been in operation have established that a block can be lifted out of the paving without disturbance of the adjoining blocks, and there is evidence that the lifting of a block occurs when its leading edge is slightly above the surface of the one next above it, com- bined with a certain minimum width of joint giving the movement room to take place. Since the joints in the apron are open and the apron and river- bed below the weir become perfectly dry in the summer, it is reasonable to assume that the upstream curtain has become quite staunch ; if this is so, the maximum head that could conceivably cause upthra t on the base of a block situated in the region of block movement, when water is passing over the weir, is insufficient to lift the block out. The movement is probably mechanical and may be due to the setting up of oscillation which joggles the block up somewhat on the analogy-not a very satisfactory one-of the manner in which a paver joggles a set out of a paved road. The effect has been reproduced on a 1/30 scale model with a depth of water ,

corresponding to 1 metre passing over the crest, but very little enlighten- ment was obtaihed as to the cause or process of the lifting of the model block.

It has not been possible to observe the conditions of flow at the weir which sets up this movement, but it is significant that such damage as has occurred to the apron in the three years has all been within the range of maximum turbulence of the standing wave (Pig. 18). It would seem, therefore, that 'it is this section of the apron in a weir of this design that is the danger zone and requires different treatment in design. Experi- ments were made on the model with this section laid with headers only, when no movement of a block was produced under any conditions of flow ; but the result can only be considered negative, as other experiments with the blocks all laid as stretchers also showed no movement when care was taken to see that they were laid with tight joints. In this connexion it may be of interest to record that the aprons of the weirs downstream of t.he

Page 27: J.D. Atkinson_Diyala Weir

44 ATKINSON AND CARDIACOS ON

Delta barrages in Egypt, where both Authors were stationed for severa.1 ye,ars, which were constructed in 1901 and are paved with rectangular blocks of stone laid entirely as headers, have not, so far as is known, shown this movement.

The stretcher blocks of the Diyala weir have dimensions of 1.50 metre by 0-50 metre by 0.40 metre (4.92 feet by 19.68 inches by 15-75 inches) and weigh dry about 675 kg. (1,485 lb.) ; the upward pressure on the base of such R. block required to overcome its residual mass when submerged is only 0.71 lb. per square inch, but in the case of a header it is 1-27 lb. per square inch.

AR a result of these observations it is proposed to relay the section to

Fig. 18. US. 6740 fzxd US. 67.50 D.S. 65,624

Scale l: 600

which the movement of the blocks is confined entirely with headers should holes recur in any of the bays, necessitating relaying.

In each of the three years the bed of the river below the weir dried up completely, as did the apron, and no springs or seepage have been observed. Slight leakage through the expansion joints has appeared each year, but in diminishing quantities. No abrasion has been observed on any of the exposed surfaces of the mass concrete of the main weir, abutments or walls, although some slight spalling has occurred a t some of the expansion joints.

Discharges were measured in the river below the structure in order to ascertain the discharge formula of the weir, which was found to be : Q = 780 d1.6, where Q denotes total discharge, in cubic metres per second, and d denates depth of water above crest-level, in metres, as measured from the upstream gauge.

The formula derived from the early model experiments referred to in the text gave discharges 3 per cent. higher than the above. Pig. 19 shows the reconstructed weir.

The work described above was carried out in a very satisfactory manner

Page 28: J.D. Atkinson_Diyala Weir

THE RECONSTRUCTION OF THE DJYALA WETR. 45

by local contractors under the supervision of the Irrigation Directorate of the Iraq Government, and this Paper is submitted with the permission of H.E. the Minister of Communications and Works.

The Paper is accompanied by an Appendix and by sixteen sheets of drawings and sixteen photographs, from some of which the folding Plates, the half-tone Plates and the Figures in the text have been prepared.

APPENDIX

COSTS.

1936. Supply and driving of Ougr6e sheet-piles. ‘ 10-metre piles : 212.67 metres a t 41.5 Iraq Dinars* = 8,825405 Dinars

5-metre piles : 220.58 metres a t 21-0 Iraq Dinars* = 4,632.180 ,, 1939. Supply of Ougr6e sheet-steel piles.

} 831.875 tons 5-metre

1939. Contractors’ account.

= 15,535,423 ,,

Description.

Provide cofferdam . . . . . . . Excavation in gravel : cubic metres . . Gravel filling: cubic metres . . . . Breaking up old concrete : cubic metres . Concrete in divide walls : cubic metres . Concrete in stepped core walls : cubic

metres . . . . . . . . . Making concrete blocks :

0.65 X 0.65 X 0.65 metre : number . Expansion joints: number. 0.4 X 0.4 X 0.2 metre : number . .

Driving 10-metre Ougr6e piles : metres . 1, 5 , , ,, ,, ,, 1 , .

Pumping, with erection of pumps . . . Providing and fixing tie-bolts : number . Excavation in trial pits : number . . . Protection filling in block concrete : cubic

metres . . . . . . . . . . Protection filling in large blocks : number Construction of Resident Engineer’s house Construction of kitchen and garage . .

. . . .

- ! 1 Rate.

Quantity. Actual ~

Dinars.

One job

0 1,762.45

0 8,926.99 0 5,710.97

LumI

530.55 2

2,71047 2

145 0 2,750 0

5 281.15 12

3

721.10 6

155 4

0 2

209 145

0 0

One job Lump

- -

- -

Total

1 . -

) S

Ms.

um 050 100 500 600

500

800 110 000 000 000 um 240 000

100 050 - -

Total Amount.

Dinars. Fils.

500 349 446 000

6,777 185

116 000 302

200 37 000 300 600 4,326 800 3,373 000 15 500

000 8

20 900 7 250

263 030 725 809

20,051 386 - -

* 1 Iraq Dinar = 1,000 fils = El.

Page 29: J.D. Atkinson_Diyala Weir

46 ATKINRON AND CARDIACOR ON THE RECONSTRUCTION OF THE DIYALA WEIR.

1940. C’ontructors’ account.

Description. l Excavation in gravel : cubic metres . . Filling in gravel under downstrram apron :

Filling in gravel, upstream side : cubic . . . . . . . . cubic metres

metres . . . . . . . . . . Filling between old and new right bank

. . . . Concrete core of weir and divide walls :

Concrete for vertical face of weir : cubic

Concrete for lip wall : cubic metres . . ,, stretchers and headers : square

,, skin of weir : cubic metres . metres . . . . . . . . . .

Steel reinforcement for core of weir : tone Steel fabric on upstream face of weir:

Demolition of old concrete slab: square square metres

Screened gravel under blocks and right metres

bank pitching : cubic metres . . . . Transport of pre-cast blocks : number .

Removal and reconstruction of pre-cast

Moulded concrete in pre-cast blocks for block pitching : square metres

Concrete step gauge : cubic metres . . pitching : square metres

Downstream gauge pilasters : number . Concrete footing for downstream pitched

Bitumenized gunny for joints in core of

Bitumenized gunny for joints in divide

Platform in concrete for abutments:

Steel ladders: number Concrete abutments : cubic metres . . Footing upstream pitching on right bank :

Removal of old concrete slab : square

Cleaning of piles : square metres Demolition of old concreto : cubic metres Removal of old stccl pilcs : metres . .

abutments: cubic metres

cubic metres

metres

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . .

. . . . . . slopes : cubic metres

weir : number

walls : number

square metres

. . . . . . . . . . . . . . .

. . . . . . . . . . . . . .

. . . . . . . . cubic metres

metres . . . . . . . . . . . . .

duantity. Actual

12,326.18

13,122.12

765.00

3,480.48

3,351.76

1,169.59 641.34

948.48

13,655.73 14.68

140.00

9,644.83

4,843.99 9

152.74

467.14 5-25 4

186.33

64

18

69.80 2

310.09

35.92

k,961.15 3,217.08

361.14 104.11

Ratc.

,inars

0

0

0

0

2

2 3 3

30 2

0

0

0 0

0

0 3 6

3

4

4

0 15 5

3

0 0 0 0

~

Fils. -

120

120

120

120

500

750 500 500

000 OOO

200

100

150 100

200

800 000 000

000

000

000

000 600

000

000

050 010 800 750

Cotal

Potal Atnonnt.

Dinars.

1,471)

1,574

91

417

8,379

4,093 1,763

3,319

27,311 422

28

964

726 0

30

373

24 15

558

256

72

30 41

1,550

107

98 32

288 78

54,131

- Fils. -

142

654

800

658

400

685 665 680

460 400

000

483

598 900

548

712

000 750

990

000

000

880 000 450

760

057

912 171

082

385 -

Grand total . . . 103,176 Dinars 530 fils.

Page 30: J.D. Atkinson_Diyala Weir

T H E R E C O N S T R U C T I O N OF T H E DIYALA WEIR.

l MAP OF DIYALA RIVER AND ITS CATCHMENT.

.A

PLATE I.

FIG. 2

DIYALA WEIR, GAUGES AND DISCHARGES AT FLYING BRIDGE.

WILLIAM CLOWES Bi SONS, LIMITED, LONDON. The Institution of Civil Engineers. journal. November, 1945. J. D. ATKINSON and

G. CARDIACOS.

Page 31: J.D. Atkinson_Diyala Weir

PLATE Z T H E R E C O N S T R U C T I O N OF T H E DIYALA WEIR.

Hand rair FIG. 10 Hand rail

Prsurt concrete

I Q

Total length of lip wall 438.11

PLAN S a l e 1 : 2000

COMPLETION PLAN 1940.

J. D. ATKINSON and G. CARDIACOS. The Institution of Civil Engineers. Journal. November. 1945. WILLIAM CLOWES & Soas, LIMITED, LONDON.