Moment capacity

Tensile membrane behavior requires continuous reinforcement steel to support in-plane stesses. Two-way slabs and flat slabs, with fixed or simple supports, can usually satisfy the requirements for tensile membrane resistance. Design with tensile membrane resistance is the same as for flexural resistance since the moment capacity of the section is used to determine ultimate resistance. Tensile membrane resistance at 8 degree rotation must be at least... 

M is the ultimate moment capacity at midspan M psis the ultimate moment capacity at support. 

Increase moment capacity of structures by adding new lateral bracing between structural elements. 

A typical shear connection for a wall girt might consist of a relatively thin two bolt shear tab. As a blast load is applied to the girt, tearout of the tab may occur due to an inadequate number of bolts or insufficient weld capacity. This will prevent development of plastic moment capacity of the member and thus reduce its blast resistance. A typical upgrade for this type of connection is addition of a new shear tab wetded or bolted to the existing column and girt. 

Flexural members which must develop moment capacity at the end of the member may be inadequate because they were designed for predicted member stresses due to... 

Many roof beams, roof purlins and wall girts in existing petrochemical structures are not capable of developing their full plastic moment capacity for loads in the plane... 

Note that the section modulus, S, is used to compute the moment capacity instead of the plastic section modulus, Z, mainly because section modulus values arc readily available. The difference is minor due to relatively low response and due to capacity reductions from buckling of the thin web. 

Bracing - Members should be braced in accordance with AI SC specification requirements to develop full moment capacity of each member. Both flanges should be braced to accommodate rebound forces. 

Midlands police car park soon after construction, as a result of a deficiency in conventional reinforcement, has been well publicised. Here again, additional bonded plate reinforcement was installed in order to control further cracking under live load. An 11 m span, 2 m deep reinforced concrete beam at a shop in Bootle was strengthened to provide a 10% increase in ultimate moment capacity. In so doing it was calculated that the mean horizontal shear stress resisted by the adhesive was 9.84 N/mm. ... 

It was hoped that frame failure would initiate in the connections. However, it appears that initial imperfections (identified in a cross-section dimension survey reported in reference 5 promoted local buckling in the beam compression flange which eventually resulted in cracking of the web-flange junction at mid-span before the moment capacities of the beam-column joints were exhausted. 

The ultimate curvature is determined when, at the end of a pre-determined number of complete cycles to 0mj one of the following limit states is reached (a) a 20% reduction in the moment capacity (b) the transverse steel reinforcement reaches its capacity to absorb energy From the energy balance of the cross-section, the concrete ultimate compression deformation is calculated (c) the maximum tensile or compression deformation of the longitudinal reinforcement is reached. 

Balanced Strain Condition Balanced strain condition corresponds to the strain distribution where the extreme concrete strain reaches 0.003 and the strain in reinforcement reaches yield at the same time. At this condition, the section has the highest moment capacity. For a rectangular section with reinforcement in one face or located in two faces at approximately the same distance from the axis of bending, the balanced factored axial resistance, P, and balanced factored flexural resistance, M, maybe computed by... 

From these lines, one can see that below the balanced condition the moment capacity increases with the increase of axial load. So, when designing a column, it is not enough to simply take a set of maximum axial load with maximum bending moments. The following combinations should to be evaluated ... 

The behavior of a pile group under lateral loading is not well defined. As discussed in the earlier sections, the lateral moment capacity is greater than the sum of all the piles in a group because piles would form couples resulting from their axial resistance through the action of the pile cap. However, the capacity of a pile group to resist lateral loads is usually smaller than the sum of separate, individual piles because of the interaction between piles. 

Nominal moment capacity calculation Vertical direction positive moment ... 

Nail force convert from moment capacity... 

Nail force per moment capacity on vertical direction... 

Seismic isolators reduce the super structure drift and acceleration at the cost of increased displacement at the base. The theory is that most of the earthquake input energy is dissipated at the base level with little to pass to the super structure. But in near field seismic motions the base itself experiences out of limit base displacement. This on the other hand increases safety concern, as with little moment capacity at the base, large base deflection can topple the building or the building may collide with nearby structures. The hybrid... 

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