Prof.Kodali Srinivas

A structural member loaded axially in compression is generally called a compression member. Vertical compression members in buildings are called columns, posts or stanchions. A compression member in roof trusses is called struts and in a crane is called a boom. If the load on a column is applied through the center of gravity of its cross section, it is called an  'axial load' . A load at any other point in the cross section is known as an eccentric load.  As the axial load on a perfectly straight slender column with elastic material properties is increased in magnitude, this ideal column passes through three states: a)Stable equilibrium :     The straight column under load is in stable equilibrium if a lateral force, applied between the two ends of the column, produces a small lateral deflection which disappears and the column returns to its straight form when the lateral force is removed. b)Neutral equilibrium : If the colum...

A  cable  is most often two or more wire  running side by side and bonded, twisted or braided together to form a single assembly.  Cables  are used for lifting, hauling and towing or conveying force through tension.  Cables are commonly used to support suspension bridges, as permanent guys for transmission towers, chimneys and building roofs. Analysis of cables : Cables are perfectly flexible members which are assumed to have no flexural strength. They carry loads by simple tension. The reactions at supports (Ra,Ha,Rb,Hb) will be calculated by using three static equations and forth equation is obtained from consideration that the Bending moment at any point in the cable is zero. Shape of the cable:   Cable subjected to concentrated loads, will take the shape of funicular polygon .  cables - parabolic shape   If it is loaded with uniform distributed load along the horizontal span, it will take t...

The arch is one of the oldest structures. The Romans developed the semi circular true masonry arch.which they used extensively in both bridges and aqueducts.  An arch is a curved beam in elevation. The horizontal moment at the supports is wholly or partially prevented in arches. Hence a horizontal thrust induced at the supports. The supports must effectively arrest displacements in the vertical and horizontal directions in the arch action. Types of Arches Based on their geometry, arches can be classified as semicircular, segmental, or pointed. Based on the number of internal hinges, they can be further classified as two-hinged arches, three-hinged arches, or fixed arches.  An arch with a hinge at each support and third hing at the high point / crown or any where in the rib of arch is known as Three Hinged Arch . An arch with a hinge at each support and no hinge exists anywhere in the rib, it will called as a Two-hinged arch. An arch without hinges at  supports and...

Analysis of multi-storey building frames involves lot of complications and tedious calculations by using conventional methods. To carry out exact analysis is a time consuming task. Substitute frame method for analysis of multistory frame can be handy in approximate and quick analysis. This method has been applied only for vertical loading conditions.  Substitute frame method  Substitute frame method assumes that the moments in the beams of any floor are influenced by loading on that floor alone. The influence of loading on the lower or upper floors is ignored altogether. The process involves the division of multi-storied structure into smaller frames. These sub frames are known as Equivalent frames or Substitute frames. The substitute frames are formed by the beams at the floor level under consideration, together with the columns above and below with their far ends fixed.  The sub frames are usually analyzed by the moment distribution method, using only Two cycle of dist...

The behavior of a structure subjected to horizontal forces depends on its height to width ratio. The deformation in low-rise structures, where the height is smaller than its width, is characterized predominantly by shear deformations. In high rise building, where height is several times greater than its lateral dimensions, is dominated by bending action. To analyze the structures subjected to horizontal loading we have two methods. Portal method  and Cantilever method 1. PORTAL METHOD The portal method is an approximate analysis used for analysing building frames subjected to lateral loads such as Wind loads/ seismic forces.  Since shear deformations are dominant in low rise structures, the method makes simplifying assumptions regarding horizontal shear in columns.  Each bay of a structure is treated as a portal frame, and horizontal force is distributed equally among them. Assumptions in portal method   1. The points of inflection are located at the mid-height of e...