Midterm Research #1 (Building Technology)

8/8/2019 Midterm Research #1 (Building Technology)

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(A.1) Live Loads

The live load is variable, and consists of the weight of people, furniture, stocks of goods, machinery, etc.

The amount of this load, which should be added to the dead load, depends upon the use to which the

building is to be put. Where the floor is required to support a considerable live load, concentrated at a

particular place, such as a heavy safe or piece of machinery, special provision should be made in the

floor construction for it. Table V gives the live loads per square foot recommended as good practice in

conservative building construction.

Live Loads. Lb. per Sq. Ft.

Dwellings, offices, hotels, and apartment houses ............................ From 40 to 70

Theaters, churches, ballrooms, and drill halls................................... From 80 to 120

Factories............................................ From 150 up

Warehouses......................................... From 150 to 250

A live load of 70 lb. per sq. ft. will seldom be attained in dwellings; but, as city houses are liable to be

used for other than dwelling purposes, it is not generally advisable to use a lighter load. In country

houses, hotels, etc., where economy demands it, and the intended use for a long time is certain, a live

load of 40 lb. per sq. ft. of floor surface is ample for all rooms not used for public assembly. For such

rooms, a live load of 80 lb. per sq. ft. will usually be sufficient, as experience shows that a floor cannot

be crowded more than this. If the desks and chairs are fixed, as in a schoolroom or church, a live load

over 40 to 50 lb. will never be attained.

Office-building floors have been designed for a live load ranging from 20 to 150 lb. per sq. ft., but a

conservative practice is to use about 70 lb. per sq. ft.An investigation of the live loads in over 200 office

buildings in Boston showed that the greatest live load in any office was 40 lb. per sq. ft., while the 10

heaviest loaded offices averaged 33 lb. per sq. ft., the average live load for the entire number of officesbeing about 17 lb. per sq. ft.

Retail stores should have floors proportioned for a live load of 100 lb. and upwards; while, for wholesale

stores machine shops, etc., a live load of at least 150 lb. per sq. ft. should be figured on. The static load in

factories seldom exceeds 40 to 50 lb. per sq. ft. of floor surface, and usually a live load of 100 lb.,

including the effect of vibrations due to moving machinery, is ample. The conservativerule is general, to

assume loads not less than the above, and to be sure that thebeams are proportioned to avoid excessive

deflection. Stiffness is a factor as important as mere strength.

In designing the floors of office or buildings of l ike character, it is good practice to figure the full live load

on the floor joists or beams, but to consider only a certain percentage as coming upon the girders,columns, and foundations, on the assumption that all of the floors will not be fully loaded at the same

time. This percentage should be carefully considered in each case; and the amounts will depend upon

the height of the building in question and the judgment of the designer.


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In proportioning the foundations of hotels, office buildings, etc., the live load may be neglected, but

should be considered in heavy warehouses. In buildings carrying heavy machinery causing much

vibration, it is good practice to double the estimated live load.

(A.2) Dead loads

This is the weights of materials, equipment, or components that are relatively constant throughout the

structure's life. Permanent loads are a wider category that includes dead loads but also includes forces

set up by irreversible changes in a structure's constraints for example, loads due to settlement, the

secondary effects of pre-stress or due to shrinkage and creep in concrete.

Also, dead loads are not limited to walls, floors, roofs, ceilings, stairways, built-in partitions, finishes,

cladding and other similarly incorporated architectural and structural items, and fixed services

equipment, including the weight of cranes. All permanent loads are considered dead loads.

B. Reinforced Concrete slab

(B.1) One-way slab

It is supported on four sides and has a much larger span in one direction than in the other may

be assumed to be supported only along its long sides. It may be designed as a beam spanning in the

short direction. For this purpose a 1-ft width can be chosen and the depth of slab and reinforcing

determined for this unit. Some steel is also placed in the long direction to resist temperature stresses

and distribute concentrated loads. The area of the steel generally is at least 0.20% of the concrete area.

(B.2) Two-way slab

A slab supported on four sides and with reinforcing steelperpendicular to all sides is called a two-way slab. Such slabs generally are

designed by empirical methods. A two-way slab is divided into strips for

design purposes.


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BalustradeA balustrade provides protection on the open sides ofa stair.

Rise This is the vertical distance between the upper surface of two consecutivetreads.

Going This is the horizontal distance between nosing of two consecutive.

Types of Stair

Stairs could be classified according to its plan form as follows.

Straight Flight

Dog Leg Stair

Open Wall Stair


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Geometrical Stairs

Construction of Stairs

According to it's construction, stairs are categorized as follows:

01. Brick Stairs:-- Brick stairs used for external steps & stairs.

02. Stone Stairs:-- These are very expensive; and are rarely used.

03. Concrete Stairs:-- These are widely used in all types ofbuildings. These are strong, fire resistant

and make possible a wide range offorms.

04. Timber Stairs:-

- These are economical & lightweight. Commonly used in domestic buildings.

Brick Stairs

y Step 1

Remove the existing stairs if there are any. If

you have a set of brick steps that are in

disrepair, the easiest and best thing to do is get

rid of them altogether and start over.

y Step 2

Excavate the soil to below the frost line using a

shovel. Compact and level the ground to

prepare it for cement.

y Step 3


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Construct the frame for the cement using 2 by

4s lining the perimeter.

y Step 4

Mix the cement according to the package

instructions and pour it into the base. Screed

the cement level and allow it to cure as

directed. The cement base will provide stability

to the brick porch steps.

y Step 5

Measure from the base to the top of the porch

to determine how high steps need to be, also

called the "total rise."

y Step 6

Determine how high you want the rise of each

step to be to satisfy the total rise. This will

require a little creative math since bricks

generally have fixed dimensions. Play around

with different patterns to get the rise you need.The rise on a brick step is usually between 6 and

7 1/2 inches.

y Step 7

Wet the bricks with a garden hose a couple hours

before you start to work with them.

y Step 8

Mix the mortar according to the manufacturer's

directions.

y Step 9

Lay a 1/2-inch layer of mortar on the concrete

base and use the screed to level it.

y Step 10

Lay the bricks according to your pattern, leaving

a 1/2 inch of space between them. You can use

temporary form bars to guide you in a straight

line. Set the bricks into the mortar with a tap

from the mallet.

y Step 11

Fill the spaces between the bricks with mortar

using the trowel and move on to the next layer

in your pattern.

y Step 12

Finish the look, tooling the exterior joints with a

concave jointer tool.

y Step 13

Remove excess mortar from the bricks with a

stiff brush after the mortar has set a little but

isn't entirely cured.

Stone Stairs

Here are the things you really need:y Stone steps

y Step Riser

y Back riser

y Gravel

y Galvanized spike nails

y Plastic clips

y Manual gravel compactor

y Mechanical plate compactor

y Hammer drill

y Stone cutter

y Construction sand

y Broom

y Lever

y Sweat and patience


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Here is how all the bits and pieces are fitting together:

And here are the steps for building your stone stairs:

1. Make sure the base thoroughly compacted and perfectly leveled.

2. Nail the first row of step risers to the base and seat the back risers

3. Attach the plastic clips to the stone steps, glue and seat the stone steps on top of the first row of step

risers and back risers.

4. Fill with gravel to the height of the first row of stone steps and thoroughly compact the gravel by

using the mechanical compactor. Check that the compacted gravel is properly leveled and at the height

of the first row of stone steps. If not, add or remove gravel as appropriate and compact further

5. Repeat the above steps for all subsequent rows of

stone steps with the exception of the last one

At the last row, add gravel to the level of the row of

risers less the thickness of the top patio stone. In

general the thickness of the patio stone is equal to

the thickness of the stone step.


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6. Add lime stone and make sure the top of the gravel is properly leveled. Then seat the top patio stone

according to you patio stone layout, starting from one corner. Please be aware that some patio stairs

designs may require a stone cutter in order to make all the pieces to fit together.

7. Add sand in between the top patio stones only and wipe out the excess by using a broom. I have

always used construction sand for this purpose although you could use polymeric sand which may better

inhibit the growth of vegetation in between the patio stones. Since the polymer-based sand tends to be

quite expensive and not fully proved, I have always used organic alternative and very effective ways for

getting rid of unwanted vegetation.

Here is how my patio stone stairs look like.

Concrete Stairs

y Step 1

Determine the size of the steps you want to use. For

a step height (rise) of 4 to 4 1/2 inches, the tread

depth should be 18 to 19 inches. For a step height of

5 to 5 1/2 inches, the tread depth should be 16 to 17

inches. For a step height of 6 to 6 1/2 inches, the

tread depth should be 14 to 15 inches. For a step

height of 7 to 7 1/2 inches, the tread depth should

be 10 to 11 inches.

y Step 2

Cut the side pieces for the form, known as stringers,

using step dimensions from Step 1. Slope each step

downward about one-quarter inch so that water can

run off. Use one-quarter-inch plywood. Angle each

stringer so that the bottom edge slopes upward. You

will be making concrete stairs that rise upward

rather than a solid mass of concrete.

y Step 3


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Cut the one-quarter-inch plywood that will support

the underside of the stairs. Choose the stair width

you want, but avoid making it wider than 3 feet for

this project.

y Step 4

Attach the plywood support to the stringers with

duplex (double-headed) nails. The plywood supportshould extend 1 foot wider than each stringer.

y Step 5

Nail pieces of 1-by-4-inch wood to the exterior of the

form, bracing the stringers against the plywood

support. Put the bracing blocks every 2 feet.

y Step 6

Saw 2-by-8-foot boards, rip them lengthwise to

match the height of the rise, and nail them to the

front of each step to keep freshly poured concrete

inside the form.

y Step 7

Lay the form on top of the support built in the next

section.

Building Support for the Underside

y Step 1

Saw 4-by-4-inch posts and place them upright on 1-

inch thick squares of wood for later removal. You'll

need at least four, possibly more, depending on stairheight. Cut the tops at an angle to match the upward

angle of the concrete stair form.

y Step 2

Lay 4-by-4-inch posts atop the vertical 4-by-4's,

nailing them in place. These posts will provide

support under each stringer as it angles upward.

y Step 3

Add support across the width of the stair by putting

2-by-6 boards across the 4-by-4's added in Step 2.

Nail the boards together.

Timber/Stringer Stairs

Basic Stair AnatomyThere are three main components in a typical staircase: stringers, treads and risers. Stringers, typically cut from 2 x

12s, are the sloped boards that support the other components and carry the weight of people walking on the stairs.

They're typically spaced 16 in. on center. When determining the staircase width, remember that wider is better. "Wide

staircases are more comfortable and safer to walk on," says remodeling contractor Paul Mantoni, of Exteriors Plus in

Terryville, Conn. "I seldom build one less than 4 ft. wide, and prefer them a bit wider."

Treads form the top surface of each step, and risers are installed directly under the front lip of each tread. Some

stairs don't have risers, but that's a mistake, according to many builders. "Risers protect the exposed endgrain of the

notched stringers from the weather," explains award-winning deck builder Scott Padgett, of Idyllwild, Calif. "Without

risers, stringers will crack or split much sooner."


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Step 1: Calculating Rise and Run

The first step in building stairs for a deck is finding the total rise or overall vertical height the stairs have

to cover. Lay a straight board on top of the deck, extend it from the edge, then measure down to the

landing location. Let's say the total rise is 57 in. The next job is to find the rise of each step. Divide 57 by

7 in. (the typical rise per step) to get 8.14. Round down to get the steps: eight. To then determine the

actual rise, divide the 57 in. by the eight steps to get 7 1/8 in. per step.

You can use that information to find the total run of the staircase--or how much horizontal distance it

will cover as it climbs. Multiply the number of steps by the run, or horizontal depth, of each step. The

optimum run of each step is no less than 10 in., which is enough space to accept two 2 x 6 treads. In ourexample, the staircase has eight steps, so the total run is 80 in.

There is one wrinkle in the math, however: If you are working with a tall deck, it's a good idea to break

up the staircase with intermediate landings. "As a practical matter you're limited to about 14 steps

because that's the most you can cut [in a stringer made] from a 16-ft.-long

2 x 12," says Andy Engel, author of Building Stairs (Taunton), "but I prefer

adding a landing after every seven or eight risers."

Step 2: Cutting StringersBefore laying out the steps on a 2 x 12, decide how the stringers will join the deck.

They're either attached directly to the rim joist so the top step is flush with the deck

top, or to the framing under the deck, which is the way we did it (see drawing on

previous page). When mounted under the deck, the stringers are either attached to

the joists or to blocking placed between joists, and the stringer ends are cut long to

reach the framing.

Mark the tread notches using a framing square fitted with stair gauges. These small

brass fixtures clamp onto the square, providing an accurate way to mark several


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identical notches. Clamp one stair gauge on the square's tongue directly at the rise dimension. Attach the other

gauge to the body of the square at the run dimension. Then, lay the square on the 2 x 12 with the gauges pressed

against the board's edge and mark the tread and riser. Slide the square down, align it with the previously drawn

notch, and add the next one.

Cut the notches using a circular saw, being careful not to go beyond the lines. Finish the cuts with a jigsaw or a

handsaw.

Next, trim the bottom of the stringer an amount equal to the tread thickness. For example, if you're installing 2 x 6

treads, cut 1 1/2 in. from the bottom of the stringer. Use the first stringer as a template to mark the remaining

stringers.

We screwed each stringer to the deck-frame blocking, which was spaced 16 in. on center. With the stringers in place,

check that each step is level, and use a block plane to shave down high spots.

Step 3: Installing Treads and RisersCut the risers to length and fasten them to the stringers with 2 1/2-in. trim-head decking screws. Note that we cut therisers and treads to overhang the outer stringer by 1 1/4 in. Later, a 1 x 12 cedar trim board will be nailed to the

stringer, giving the staircase a more finished look. This detail isn't always necessary.

After installing the risers, fasten the treads with screws. Leave a 1/8- to 1/4-in. space between the treads. Continueinstalling treads, working your way up the staircase. The 4 x 4 posts used to support the stair rail are typically boltedto the stringers before installing the treads. However, we completed the stairs first, and then attached the posts andbuilt the handrail that codes usually require.

(C.2) Stair Stringers

y Stair stringers form the structural support of a basic staircase. Two sloped pieces of wood,

extended from one floor level to the next, create the backbone on which the steps and risersrest. A contractor may at times choose to add a third stair stringer for added support, which

would run down the center of the staircase, in between the other two.

Types

y There are two types of stair stringers. Looking at a staircase head on, the 'open string' appears to be

suspended between the two floors, unobstructed. The stair strings are openly visible on both sides, with


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no walls on either side, only banisters and rungs. The second type is the 'closed stringer' which is

attached to the wall. In this type, only one side of the staircase is attached to a wall, with the other side

harboring a banister and rungs or in some cases such as, basement stairs, both sides may be attached to

running walls.

Size

y It is recommended when building a staircase that each step is no less than 36 inches wide,

with a depth of at least 12 inches. The risers also have a recommendation, which is at least 8

inches in height. When building stair stringers, it is important to take this information into

account. And in deciding the length of each stringer, the vertical distance of the proposed

staircase must be measured, and divided by 8 (remember: the riser heights will be 8 inches

each). Round your quotient to the next whole number, which will in turn, give you the amount of

steps that will be necessary to build the staircase. For instance, if you measure a vertical

distance of 144 inches, divide that figure by 8, your answer will be 18 steps (144 8= 18).

Considerations

y The strength of your staircase needs to be considered when choosing the wood to build it. A

contractor will normally opt between 2 by 10 and 2 by 12 foot lumber pieces, With the 2 by 10 being

the most supportive, and preferred, when an open string staircase is being built. The extra 2 inches of

support may not seem like a big difference, but it can be of tremendous benefit if the staircase will also

need to support the weight of a heavier person.

Warning

y A durable staircase requires woods that can hold up against a daily barrage of weight and foot traffic.

Choosing a high quality wood is important, and viewing the wood before purchasing is a necessity.

Wood that will be used for stair stringers must be free of any bowing or warping. For aesthetic purposes,

wood that is free of large knots is also preferred.


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D. Roofing Structure

(D.1) Types/Shapes of Roofs


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(D.2) Types of Roof Frames


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(D.3) Various Kinds of Roof Rafters

Only seven different types of roof rafters are required to build the most complex roof.A simple

gable roof can be constructed using only one type, the common rafter. Three different types the

common, hip, and hip jack rafters are all needed to frame a hip roof.

These rafters can be cut from standard framing lumber, laminated veneer lumber, glued

laminated beams, timbers, steel, or I beams made from wood called TJI's.

Types of Rafters

Common Rafters are found in all conventionally framed roofs and run from an exterior wall all the way

up to the ridge board. They are used to set the height and center the ridge board in the span.After the

ridge board location has been established the hip and valley rafters location can then be be established.

Hip Rafters run at a 45 degree angle to the commons and are placed from the outside corners of the

building to the ridge board.

Hip Jacks sit on the outside walls and run up to the hip rafter in line with the common rafters.

Valley Rafters are placed at inside corners to the ridge and are also at a 45 degree angle to the

commons.

Valley Jacks run from the valley rafter up to the ridge board and in line with the commons.

Cripple Jacks are used when a valley and hip are located close together and only go from a valley to a

hip rafter.

Flying Hip also known as a mystery hip go from where a valley rafter meets a ridge to the end of a higher

ridge board.


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Location of Roof Rafters

The illustration below may give you a better idea of where the different types of rafters are located

when framing a roof.


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BUILDINGTECHNOLOGY

II

PREPARED BY:

DELOVINO, EDGAR JR. C.

SUBMITTED TO:

ARCH. TOMAQUIN

INSTRUCTOR

Documents

Midterm Research #1 (Building Technology)