See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/258590981 Shear Wall Construction in Buildings: A Conceptual Framework on the Aspect of Analysis and Design Article in Applied Mechanics and Materials · December 2012 DOI: 10.4028/www.scientific.net/AMM.268-270.706 CITATIONS READS 0 9,689 4 authors, including: Muhammad Abu Eusuf Khairuddin Abdul Rashid International Islamic University Malaysia International Islamic University Malaysia 28 PUBLICATIONS 290 CITATIONS 26 PUBLICATIONS 31 CITATIONS SEE PROFILE Abdullah Al Hasan 4 PUBLICATIONS 1 CITATION SEE PROFILE Some of the authors of this publication are also working on these related projects: “Campus Quality of Life (CQoL): Analysis on the impact of climate change” View project Wellington Park Artwork Design Competition View project All content following this page was uploaded by Muhammad Abu Eusuf on 15 October 2014. The user has requested enhancement of the downloaded file. SEE PROFILE Applied Mechanics and Materials Vols. 268-270 (2013) pp 706-711 © (2013) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/AMM.268-270.706 Shear Wall Construction in Buildings: A Conceptual Framework on the Aspect of Analysis and Design Muhammad Abu Eusuf Ph. D1, a & Khairuddin A. Rashid, Ph. D2, b, Wira Mohd. Noor, Ph. D3, c and Abdullah Al Hasan4, d 1, 2 Faculty of Architecture and Environmental Design, International Islamic University Malaysia 3 Faculty of Engineering, International Islamic University Malaysia 4 Post-graduate Student, Built Environment, International Islamic University Malaysia a [email protected]/ [email protected], [email protected], c [email protected], [email protected] Keywords: shear stress, shear wall, lateral forces, wind and earthquake prone areas, high-rise building. Abstract: This study describes the analysis and design process of shear wall construction, which is applied in various types of building construction. Shear walls resist lateral forces viz. earthquake force and wind force for high-rise structure and gravity load for all type of structure. Besides, Buildings with cast-in-situ reinforced concrete shear walls are widely used in earthquake-prone area and regions in the world. Research methods were confined to library research and employed software for analysis. The analytical accuracy of complex shear wall system have always been of concern to the civil and structural Engineering system. The software of this system is performed on the platform of modelling and then, the system models are usually idealized as line elements instead of continuum elements. Single walls are modelled as cantilevers and walls with openings are modelled as pier/ spandrel systems. In order to find the stiffness, the simple systems models can provide reasonable results. It has always been accepted that a scale based model in the FEM is exact and justifiable. Introduction Shear walls are vertical elements of the horizontal force resisting system; they can resist forces directed along the length of the wall. Once shear walls are designed and constructed properly, they will have the strength and stiffness to resist the horizontal forces [1]. It is well known to civil and structural engineering system that the key purpose of all kinds of structural systems used in building structures or any infrastructure is to support gravity loads, the most common loads resulting from the effect of gravity are dead load, imposed live load and climatic snow load. Besides these loads, buildings and any other high-rise structures are also subjected to lateral loads caused by wind; blasting or earthquake and hydrostatic load (refer to Fig. 1). Lateral loads can develop high stresses, produce sway movement or cause vibration [7]. Therefore, it is very important for the structure to have sufficient strength against vertical loads together with adequate stiffness to resist lateral forces. Shear resist mainly two types forces such as shear and uplift forces. Recently, significant figures of high-rise buildings have reinforced concrete structural systems. This is due to economic reasons. Reinforced concrete building structures can be classified as follows [8] (refer to Table 1.1). Table 1.1: Reinforced Concrete Building Structures No. 1 2 3 Systems Structural Frame Systems Structural Wall Systems Shear Wall–Frame Systems (Dual system) Description Loading system Basic elements of structural system • Frames; Floor Slab; Beams; Columns All vertical members are analyzed, design and construction as structural wall, known as shear wall. The system consists of reinforced concrete (RC) frames interacting with RC shear walls. • Carrying gravity load, while providing adequate • Carrying gravity load, lateral load such as wind and earthquake load. • Resist gravity load and lateral load Source: [8] All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 210.48.222.12-22/11/12,07:08:12) Applied Mechanics and Materials Vols. 268-270 Figure 1: Schematic diagram for force developed by earth quake 707 A render view of 3D high-rise building has been given in Fig. 2 and a typical floor plan of a shear wall-frame building structure is given in Fig. 3. It is a fact that shear walls have high lateral resistance. In a shear wall-frame system, this advantage can be used by placing shear walls at convenient locations in the plan of the building [9]. Load Sources The major types and sources of loads acted on building structures are given in the above Table 1.2. Table 1.2: List loads with sources Loads and Sources Determination Application No. 1 2 Gravity: weight of • the structural components of the building; • occupants and content; • snow, ice or water on roof Wind: Moving air; In fluid- flow action. 3 Earth quake (Seismic Shock): Shaking of the ground as result of large subterranean faults, volcanic eruptions or underground explosions. 4 Hydrostatic pressure: Principally from ground water when the free level is above the bottom of the basement. Soil pressure (active): Action of soil as a semifluid on objects buried in the ground. Thermal Change: Temperature variations in the building from fluctuations in outdoor temperature and temperature differences. 5 6 By determination of• Volume; • Density; and • Types of dispersion Anticipated maximum wind velocities established by local weather history. The wind loading is the most important factor that determines the design of tall buildings over 10 storeys, where storey height about lies between 2.7 – 3.0m. • By prediction of the probability of occurrence on the basis of history of the region and records of previous seismic activities; • Principal force effect is the horizontally impelled inertial action to the building mass. As fluid pressure proportional to the depth of the fluid. Usually by considering the soil as an equivalent fluid with a fluid density some fraction of the true soil density. • From weather histories; • Internal design temperature; and • Coefficients of expansion of the materials • Vertically downward; • Constant in magnitude. • As pressure (Perpendicular to the surface); • As Frictional drag (parallel to the surface); • As an overall horizontal force effect on the building; • Any surface may be affected in relation to its own individual geometry or orientation. • Back and forth, up and down movement of the supporting ground; • Response of the building structure on the basis of its own dynamic properties. • As horizontal pressure on walls; • Upward pressure on floors Horizontal pressure on walls. • Forces exerted on structure if free expansion is restrained; • Distortions and stresses within structure if connected parts differ in temperature 708 Materials, Mechanical Engineering and Manufacture 8 9 Shrinkage: Volume reduction Vibration Internal Action 10 Handling 7 • concrete; mortar joints in masonry; large unseasoned timber; • May produce forces similar to those caused by thermal effects. It may be caused by heavy machinery, vehicles or high- intensity sounds. Forces may induced by the settling of supports, slippage or loosening of connections, warping of elements, and so on. Forces are exerted on structural elements during production, erection, transportation, storage, remodelling, and so on. These effects are not necessarily evident in the form of finished building, but must considered in it production. Source: [2], [3], [4], [5], [6] Characteristics Load and design load The characteristics or service load is the actual load that the structure is designed to carry. These are normally considered as the maximum loads which will not be exceeded during the life of the structure. In statistically, the characteristic load has a 95% probability of not being exceeded [2]. The characteristic loads used in design and defined in BS8110: Part 1, clause 2.4.1, is as follows: a) b) c) d) The characteristic Dead Load (Gravity load) The characteristic Imposed load The Wind Load The earth quake loads Design load is the product of characteristic load and partial safety factor. The partial safety factor (given in BS8110: part 1) in Table 1.3 takes account of Possible increases in load; inaccurate assessment of the effects of loads; unseen stress distributions in members; importance of the limit state being considered. Table 1.3: Load Combination process No. Load Combinations Dead load Adverse Beneficial 1 2 3 Dead and imposed load (and earth and water pressure) Dead and wind (and earth and water pressure) Dead, wind and imposed (and earth and water pressure) Load Types Imposed Load Adverse Beneficial Earth and Hydrostatic pressure 0.0 1.4 - - 1.4 1.4 1.2 1.2 1.2 1.4 1.0 1.6 1.4 1.0 - 1.2 1.2 1.2 Wind Source: [2], [6] Location of Shear Wall Shear walls should be located on each level of the structure. It should be added to the building interior when the exterior walls cannot provide sufficient strength and stiffness or when the allowable span-width ratio for the floor or roof diaphragm is exceeded. For subfloors with conventional diagonal casing, the span-width ratio is 3:1. Shear walls are most efficient when they align vertically and are supported on foundation walls or footings. When shear walls do not align, other parts of the building will need additional strengthening. Consider the common case of an interior wall supported by a subfloor over a crawl space and there is no continuous footing beneath the wall. For this wall to be used as shear wall, the subfloor and its connections will have to be strengthened near the wall [2]. Shear walls carry the adequate lateral strength to resist incoming horizontal earthquake forces. When shear walls are well-built, they easily transfer the horizontal force to the next elements of load path below the shear walls. The next elements in the load path may be considered as another shear walls, floors, foundation walls, slabs or footings. Applied Mechanics and Materials Vols. 268-270 709 The strength of the shear wall depends on the combined strengths of its 3-components: solid wall; casing or sheathing and fastener. Strength can be reduced due to the improper installation. Fasteners for shear wall construction may be staples, screws or nails. Procedure on the Analysis and Design of Shear Wall A concept has been developed on the analysis and design of shear wall, which has been given in the following as procedure. The procedure follows some steps [7]. Step-1: Evaluate the behaviour of shear wall structures i) Lengths and thickness may change, or discontinued, at stages up the height. The effects of variation can create a complex redistribution of the moment and shears between the walls. ii) Categories shear wall is as proportionate. Non-proportionate system is statically indeterminate. a) 3.5m 3.5m 3.5m 3.5m b) Figure 2: 3-D High-rise render view Figure 3: Typical Floor Plan with Shear Wall - Frame A typical framed structure braced Building Structure-a) Schematically presents, b) by STRUDS (a structural analysis and design software) with core wall. Step-2: Analysis of Proportionate system: the system is statically determinate and then categories into ‘structure twist and non twist. 710 Materials, Mechanical Engineering and Manufacture i) Proportionate non twisting structures: A structure that is symmetrical on plan about the axis of loading. (1) ; i= level; j= wall, EI = flexural rigidity (2) ii) Proportionate twisting structures: A structure that is not symmetrical on plan about the axis of loading will generally twist as well as translate and twists under the action of horizontal load the resulting horizontal displacement of any floor is combination of translation and rotation of floor about the a centre of twist. (3) Step- 3: Analysis of non proportionate system: non-proportionate structures consist of walls whose flexural rigidity ratios are not constant throughout height, and that have different load- deflection characteristics. i) Non-proportionate non twisting structures ii) Non-proportionate twisting structures Step-4: Stress Analysis: If the wall is rectangular in elevation and has a height to width ratio greater than 5, a close estimate of the axial stresses is given by simple bending theory. If aspect ratio is less than 5:1, or if it is irregular with changes in width or openings or beam or other walls connects to it, a more detail analysis is necessary. i) Membrane finite element analysis ii) Analogous frame analysis: a) Braced frame analogy; b) axial, shear and bending stiffness; c) Application of analogous frame; d) Conversion of analogous frame forces to wall stresses Step-5: Concrete shear wall: It may be cast-inplace or pre-cast. Pre-cast panel walls are also used within a concrete or steel frame to provide lateral resistance. Coupling beams should have diagonal reinforcement to develop shear resistance. Figure 3 (opposite): A typical floor plan of shear wall buildings in European perspectives (WHE report). Conclusions The lateral loads or horizontal loads are assumed to be concentrated at the floor levels. The rigid floors stretch these loads to the columns or walls in the building. On the other hand, lateral loads are particularly large in case of high-rise buildings or when earthquake loads are considered. To mitigate or resist the large part of lateral loads, it is recommended to design reinforced concrete walls parallel to the directions of load. The lateral loads caused by wind or earthquakes act as deep Applied Mechanics and Materials Vols. 268-270 711 cantilever beams fixed at foundation system. Repeatedly, buildings have interior concrete core walls in the region of the elevator, stair case, service wells as underground water reservoir & overhead reservoir and other circulation area. There are multi-dimensional advantages of shear walls such asa) the high level of rigidness in their own plane easily can limit the adverse deflection effectively; b) act as fire compartment walls; c) ability to resist lateral wind effect at super-structure and earth motion effect in the sub- structure. However, for low and medium rise buildings (less than 10-storeys), the construction of shear walls are more time consuming and less accurate in dimensions than steelwork. Generally, RC walls acquire satisfactory strength and stiffness to resist the lateral loading system. Shear walls comprise minor ductility and may not meet the energy required under severe earthquake. Care should be taken in the design of ductile shear walls which are used to resist earthquake loads. Steel shear walls are also used sometimes, by connecting them to framework by welding or high strength bolts. Masonry shear walls are also used, with solid walls and grouted cavity masonry to carry shears and moments, with reinforcements encased. References [1] Ashraf Habibullah , S.E. Physical Object Based Analysis and Design Modelling of Shear Wall Systems Using Etabs, Computers & Structures, Inc., Berkeley, California (2003) [2] Bhatt P., Macginley T. J. and choo B. S. Reinforced Concrete: Design theory and examples, Taylor and Francis (2006) [3] British Standard, loading for buildings (LFB), BS6399-1:Part-1: code of practice for dead and imposed load (1996) [4] British Standard, loading for buildings,BS6399-2:Part-2: code of practice for wind load (1997) [5] British Standard, LFB, BS6399-3:Part-3: code of practice for imposed roof load (1988) [6] Mendis P., Ngo T., Haritos N., Hira A., Samali B. and Cheung J. Wind Loading on Tall Buildings, E. Journal of Structural Engineering: loading on structure (2007) [7] Smith B. S and Couli Alex. Tall Building Structures: Analysis and Design, John Wiley & Sons, inc (1991) [8] Taranath, B.S. Structural Analysis and Design of Tall Buildings, McGraw-Hill Company(1998) [9] Tolga Aki ¸S. Lateral Load Analysis of Shear Wall-Frame Structures, Ph. D Thesis, The Graduate School of Natural and Applied Sciences of Middle East Technical University (2004) View publication stats
