The analysis of a framed building with shear walls subjected to horizontal and vertical load is essentially a three-dimensional problem. With the proliferation of computer programs available a three-dimensional analysis presents no great difficulty provided the modeling techniques fully reflect the behavior of the structure. The only penalty is time. Sometimes, especially where a dynamic(…)
Structural Engineering
REPAIR OF POST CONCRETING DEFECTS IN STRUCTURES
The four essential features of a successful repair are: 1. Expediency: The longer the repair is left, the more work has to be done, and the less likely that the repair will blend in. 2. Cleanliness: when repairing concrete, care must be taken to remove any dirt or dust that will prevent the repair concrete(…)
SHEAR WALL – ITS TYPES AND POSITIONING
SHEAR WALL In reinforced concrete framed structures the effects of wind forces increase in significance as the structure increases in height. Codes of practice impose limits on horizontal movement or sway. Limits must be imposed on lateral deflection to prevent: Limitations on the use of building, Adverse effects on the behavior of non-load bearing elements,(…)
MEASURING LOSS OF PRESTRESS IN PRESTRESSED CONCRETE
Instruments for measuring loss of prestress in prestressed concrete: The initial pre-stressing force applied to the concrete element reduces due to elastic shortening of the concrete, anchorage losses, frictional losses etc. The pre-stressing force further reduces with the passage of time due to creep, shrinkage, temperature effect and relaxation of steel. The loss of pre-stressing(…)
MIX DESIGN OF HIGH STRENGTH CONCRETE
The properties of a high-strength concrete-mix with a compressive strength of more than 40 MPa is greatly influenced by the properties of aggregates in addition to that of the water-cement ratio. To achieve high strength, it is necessary to use lowest possible water-cement ratio, which invariably affects the workability of the mix and necessitates the(…)
OBJECTIVES OF STRUCTURAL DESIGN
The objectives of structural design is to design the structure for stability, strength and serviceability. It must also be economical and aesthetic.
STRENGTHENING OF CONCRETE STRUCTURES
When strengthening is going to be undertaken all failure modes must be evaluated. Strengthening a structure for flexure may lead to shear failure instead of giving the desired increased load bearing capacity. It should also be noted that not only the failure mode of the strengthened member is important. If a critical member in a structure is strengthened, another member can become the critical one. Because of changed stiffness in an undetermined structural system the whole structure must be investigated. The strengthening should also designed with consideration to minimize the maintenance and repair needs. When a strengthening is designed the consequences from loss of strengthening effectiveness by fire, vandalism, collision etc. must in addition be considered.
DESIGN STEPS OF RCC MEMBER FOR SHEAR AND TORSION
Design of a reinforced concrete section for shear is carried on in the following steps: (a) Determine nominal shear stress of concrete by using following formula: (b) Determine design shear strength of concrete, (Table 1 below). Table-1: Design Shear Strength of Concrete, (N/mm2) (c) Provide shear reinforcements as per requirement and convenience. Fig: Shear failure(…)