Shear capacity

Direct Shear. For type I cross-sections (0 < 2°) the concrete between the flexural reinforcement Is capable of resisting direct shear. However, because cracking at the support yield line reduces the shear capacity, diagonal bars must be provided to at least resist the shear capacity of the concrete, v. For type II and III cross-sections (0 > 2 ), with little or no concrete shear resistance, The diagonal reinforcing bars must be designed to resist the entire shear load at the support. 

Unlike most static design procedures, dynamic design requires a trial and error approach. Only in the verification of shear capacities and in the design of support connections can member proportions be directly determined. For the dynamic analysis, the needed nonlinear response properties are determined from a trial section. The analysis results then indicate the adequacy of the trial section. Experience on the part of the designer will help in reducing the number of iterations. The use of simple computer based design approaches help to reduce the time required for each analysis iteration. 

Shear reinforcing is not commonly used in wall and roof elements even though reinforced elements can undergo an extended plastic response. Shear reinforcing increases the diagonal shear capacity of the member, but more importantly, it... 

Strengthening of the connections is often the most cost effective upgrade for existing buildings if it does not require removal of existing interior walls and equipment. For a member to absorb blast energy and be structurally efficient, it must develop its full plastic flexural capacity. This requires a substantial increase in shear capacity at the connections to avoid failure. 

The roof beam is connected to the roof slab to prevent separation during rebound. In this case, the connection is to be designed to prevent composite action between the roof slab and the roof beam. Because composite action greatly increases the bending capacity while not increasing the beam s shear capacity, neglecting this effect could be very unconservative. 

Several methods are used to determine peak loads for the static design of the foundation. Such methods may be determined from the blast pressure applied to the building, the bending or shear capacities of supported structural elements, or dynamic reactions of supported elements. In this example, maximum loads from each of the components directly supported by the foundation are used,... 

Figure 11 Results of prototype tests and influence of joint quality on shear capacity. 

Damages of concrete piers as shown in Fig. 1(a) were caused by lack of flexural capacity or shear capacity of existing structures against seismic forces. Particularly, extensive damages were observed at the base part of the pier and at the termination of longitudinal re-bars at mid-height. Therefore, in piers with inadequate lateral reinforcement, it is imperative to provide additional external confinement to insure ductility of the piers. 

In 1985 cracking was noticed in the floor slabs of a multi-storey office building in Leeds. The cracks were adjacent to the external columns and the central lift well and design checks indicated a deficiency in both shear capacity and top flexural reinforcement. A combination of soffit supporting brackets and steel plates bonded to the top surface adjacent to supports was adopted to restore capacity and control cracking (Fig. 6.11). Subsequent load tests revealed that the steel plates were attracting tensile stresses up to 40 N/mm at 1.35 times design load. 

As required, transverse stiffeners were designed to provide additional shear resistance of the box section sides in order to support the rope breaking shear forces in the sheave beams. Cross-section shear capacity was determined in accordance with the requirements CSA S16-09, Clause 13.4. 

Bending capacity (cantilever a = 1, fixed a = 1/2) Shear capacity... 

A nonlinear dynamic analysis has been performed for the three monuments (Sect. 8.2.3), with the masses lumped at characteristic levels and applying a corresponding storey hysteretic model obtained by summing up the elastoplastic characteristics of each of the bearing walls, with the load-bearing capacity of each of them limited to the bending and shear capacity, whichever is less. 

Dynamic analysis With the masses lumped at two characteristic levels, a nonlinear dynamic analysis has been performed with storey hysteretic model obtained by summing up the elastoplastic characteristics of each of the bearing walls, whereas the load-bearing capacity of each of them has been limited to the lower value of bending and shear capacity (according to Sect. 8.3.3). To obtain the dynamic response, three different types of earthquake (Petrovac 1979, Ulcinj 1979 and El Centro 1940) with maximum input acceleration of 0.24g and return period of 1,000 years have been applied. Obtained as the results from the dynamic analysis are the storey displacements and ductility ratios required by the earthquake that have to comply with the design criteria defined in Sect. 8.3.4. 

The joint shear capacity based on ACI recommendation with y = 15 for exterior beam column joint is ... 

Thus the poor detailing of the joint has resulted in a loss of 40 % of the shear capacity. 

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