Analysis of Concrete Gravity Dam by 3D Solid Element Modeling using STAAD. Pro

IJSTE - International Journal of Science Technology & Engineering | Volume 1 | Issue 11 | May 2015 ISSN (online): 2349-784X

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Analysis of Concrete Gravity Dam by 3D Solid

Element Modeling using STAAD.Pro

Jay P. Patel Prof. Zalakkumar R. Chhaya

Student Assistant Professor

Department of Civil Engineering Department of Civil Engineering

Merchant Institute of Technology. Mehsana, India L.D. College of Engineering, Ahmedabad, India

Abstract

In this paper, an attempt is made to 3D modeling and analysis of gravity dam of solid element using STAAD.Pro. The load and

load combinations are taken as per IS 6512. Modelling of dam is considered in two categories, first is without openings and

second is with openings (i.e. galleries). Result of stresses and stress contours are described at the end of paper. The objective of

paper is to have a direction of analysis of dam considering solid elements using STAAD.Pro.

Keywords: Staad.Pro, IS 6512, 3D Modeling

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I. INTRODUCTION

A gravity dam is a solid structure, made of concrete or masonry, constructed across a river to create a reservoir on its upstream.

The section of the gravity dam is approximately triangular in shape, with its apex at its top and maximum width at

bottom. The section is so proportioned that it resists the various forces acting on it by its own weight. In this paper analysis of

dam is carried out using Staad.Pro software. Staad.pro is widely used for multistoried buildings with beam and columns.

However Staad.Pro can analyse any type of element such as, plate, shell or solid in addition to beam members. So, in the

software with suitable data shown below, dam is modeled with solid elements. Loadings are given as solid element pressures and

accordingly load combinations are made. The concrete gravity dam is shown in fig.

Fig. 1: Gravity Dam

II. INPUT DATA TAKEN FOR ANALYSIS

Table- 1

Input Data Taken For Analysis

Analysis of Concrete Gravity Dam by 3D Solid Element Modeling using STAAD.Pro (IJSTE/ Volume 1 / Issue 11 / 022)


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III. LOADING

Static Load: A.

1) The weight of the dam: The unit weight is determined from materials investigation. 2) Hydrostatic pressure of the water in the reservoir. 3) The uplift forces caused by hydrostatic pressure on the foundation at the interface of the dam and the foundation. Uplift

forces are usually considered in stability and stress analysis to ensure structural adequacy and are assumed to be

unchanged by earthquake forces. Table 2

Static Load



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Load Combinations: B.

1) Dam completed but no tail water 2) Full reservoir elevation Normal uplift and silt 3) Reservoir at maximum water level Normal uplift and silt 4) Load combination A with earthquake 5) Load combination B with earthquake but no ice 6) Load combination C but with extreme uplift (Drain operative) 7) Load combination E but with extreme uplift (Drain inoperative)

Result of Stress at U/S and D/S Face by Manually: C.

Table 3 Result of Stress at U/s and D/S Face by Manually

IV. GRAVITY DAM WITHOUT OPENINGS

STAAD Input and Output: A.

Nodes: 1)



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Table 4 STADD Input and Output

Solids: 2)

Table 5 Solid

V. GRAVITY DAM WITH OPENINGS

STAAD Input and Output: A.

Nodes: 1)Table 6

STAAD Input and Output



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Solids: 2)

Table 7 Solid

Solids Loads: 3)

1) Earthquake Load 2) Dead Load (Self Weight) 3) Live Load (Water pressure, Hydrostatic pressure, Weight of water, Silt pressure, Tail water pressure, Uplift pressure)

VI. STABILITY AND STRESS ANALYSIS

C.G. And Total Self Weight: A.

Table 8 C.G and Total Self Weight

CENTRE OF GRAVITY TOTAL SELF WEIGHT

X Y Z

BY EXCEL SHEET 67.18 47.10 50 45057625

BY STAAD.Pro 67.17 47.08 50 44996380

Normal and Shear Stress on Gravity Dam without Openings: B.

Table 9 Normal and Shear Stress on Gravity Dam without Openings



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Principal and Von MIS Stress on Gravity Dam without Openings: C.

Table 10 Principal and Von MIS Stress on Gravity Dam without Openings

Fig. 2: Model Structure

Fig. 3: Structure with Solid Loading

Fig. 4: Structure with 3d View



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Fig. 5: Structure with Stress

Normal and Shear Stress on Gravity Dam with Openings: D.

Table 11 Normal and Shear Stress on Gravity Dam with Openings

Principal and Von MIS Stress on Gravity Dam with Openings: E.

Table - 12

Principal and Von MIS Stress on Gravity Dam with Openings

Fig. 6: Model Structure



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Fig. 9: Structure with Solid Loading




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Fig. 11: Structure with Stress

VII. CONCLUSION

From the modeling and analysis the results can be concluded as per the following points:

1) Maximum stress in dam with openings is 4193.257 KN/m2 and without openings it is 3117.744 KN/m2. 2) The dam without openings the maximum stresses are concentrating near u/s face ranges from 0.59 N/mm2 to

0.977 N/mm2.

3) Dam with openings, Maximum stress concentrated around the openings are 4.13 N/mm2. 4) So far earthquake forces static loading is given as per the STAAD.Pro definitions and command and not

manually, however dynamic analysis is not considered in this paper.

5) There are some uncertainties still prevailing regarding stability at support conditions. In this paper Solid foundations are considered to avoid this situation.

REFERENCE

[1] Karuna Moy Ghosh,Analysis and Design Practice of Hydraulic Concrete Structure PHI Learning Private Limited [2] US Army Corps of Engineers, Gravity Dam Design EM 1110-2-2200 30 June 1995 [3] Bentley, STAAD.Pro www.bentley.com/en-US/Products/STAAD.Pro [4] IS 12966 (Part 1) -1992, Practice for Galleries and Other Openings in Dam, Bureau of Indian Standards, New Delhi. [5] IS 12966 (Part 2) -1990, Practice for Galleries and Other Openings in Dam, Bureau of Indian Standards, New Delhi. [6] IS 6512 -1984, Criteria for Design of Solid Gravity Dam, Bureau of Indian Standards, New Delhi. [7] IS 1893 (Part 1) -2002, Criteria for Earthquake Resistant Design of Structures, Bureau of Indian Standards, New Delhi.

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Analysis of Concrete Gravity Dam by 3D Solid Element Modeling using STAAD. Pro