Another method is to work out the reaction force, then work out the shear force in turn, and then draw the shear force diagram, but this method is very troublesome. The former method is simpler.
Bending moment is one of the internal moments on the cross section of the stressed member, that is, the coupling moment of the internal force system perpendicular to the cross section. Its size is the algebraic sum of all external forces on the component part intercepted by the section to the centroid moment of the section, and its positive and negative agreement is that the component is concave.
Convex is negative (the criterion for distinguishing between positive and negative is that the upper compression of the component is positive and the lower compression is negative; On the contrary, the upper tension of the component is negative and the lower tension is positive. In civil engineering, the bending moment diagram is used to be drawn on the tension side of the bar, and the plus or minus sign is not indicated on the diagram.
Extended data:
A structure that uses the inner wall or outer wall of a building as a shear wall to bear vertical and horizontal loads. Shear walls are generally reinforced concrete walls with the same height and width as the whole building. Because its main load is horizontal load, it is called shear wall because it is subjected to shear and bending. Shear wall structure has great lateral stiffness and small deformation, which is both load-bearing and enclosure, and is suitable for residential and tourist buildings.
During an earthquake, the ground motion is generated due to the action of seismic waves, which affects the superstructure through the foundation of the building and causes the structure to vibrate. The inertial force generated when the building vibrates is the earthquake load. Seismic waves may cause vertical vibration and horizontal vibration of buildings, but generally the damage to buildings is mainly caused by horizontal vibration. Therefore, the horizontal seismic force is mainly considered in the design.
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