土木工程专业英语5.2 Axially Loaded Members

1、5.2 axially loaded members,characterisitics of axially loaded members,tension members applications tension chords and internal ties in trusses tension bracing members hangers supporting floor beams sections open sections angles, channels, tees, closed sections circular, square, rectangular hollow se

2、ctions compound and built-up sections double angles/channels, round bars, flats and cables factors affecting efficiency of tension members end connections reversal load may cause buckling resisting moment,compression members applications generally described by terms columns or struts vertical member

3、s supporting floors, roofs and cranes most members are also subjected to moment besides axial load sections tend to be stocky with square sections resist buckling rolled, compound and built-up sections h-section used in buildings where axial load predominates single angles, double angles, tees, chan

4、nels and hollow sections trusses, lattice girders and bracing,design considerations,tension members possible failure modes yield in gross section fracture in effective net section block shear shear rupture along plane through fasteners bearing on fastener holes prying compression members possible fa

5、ilure modes yielding inelastic/elastic buckling flexural, torsional, and flexural-torsional flexural doubly symmetric or antisymmetric cross-sections; or singly symmetric sections (buckled about an axis that is perpendicular to the axis of symmetry). torsional doubly symmetric sections with very thi

6、n walls flexural-torsional singly symmetric cross-sections (buckled about the axis of symmetry); or unsymmetric cross-sections. local buckling width thickness ratio,design details for columns,choice of column cross-section column construction beam-column connections beam cap connections column splic

7、es not prepared for full contact in bearing, designed to transmit all moments and forces prepared for full contact, provide continuity of stiffness about both axes and resist any tension caused by bending column bases,bearing capacity short column post or pedestal fails by crushing or squashing long

8、 or slender column fails by buckling,design on column buckling global buckling for a ideal pin-ended straight column, slenderness is critical to determine the buckling load. straightness and eccentricity (imperfections) are combined with a parameter, perry factor. residual stresses caused by rolling

9、 or welding can also be taken into account by ajdusting perry factor. following aspects to be considered in global buckling design different column sections same section buckling about different axes effect of imperfections effective length,local buckling local buckling occurs in thin-walled structu

10、res shear buckling and web crippling postbuckling strength should be considered effective width used for practical design,beam columns,characteristics subjected to bending moment in addition to axial load tensile axial force induces stiffening effect; compressive axial force tends to destabilize mem

11、ber,design consideration superposition of bending effect and axial loading effect a short column subjected to axial load and uniaxial bending about either axis or biaxial bending. failure generally occurs when the plastic capacity of section is reached. a slender column subjected to axial load and u

12、niaxial bending about the major axis. column supported laterally against buckling about minor axis, it fails by buckling. a slender column subjected to axial load and uniaxial bending about minor axis. no lateral supoort and no buckling out-of-plane of bending, column fails by buckling about minor a

13、xis. a slender column subjected to axial load and uniaxial bending about major axis. column has no lateral support, and it will fail due to a combination of column buckling about minor axis and lateral torsional buckling. a short column subjected to axial load and biaxial bending. column has no late

14、ral support, and the failure same as the above item, but minor axis buckling will usually have the greatest efffect.,p- and p- effect should be considered in design member instability p- effect arises when axial force acts through lateral deflection of the member relative to its chord frame instabil

15、ity p- effect arises when axial force acts through relative displacements of two ends of the member both effects tend to increase member deflection and moment generally called p-delta effects,brief review for axailly loaded members characteristics tension members applications sections compression me

16、mbers applications sections design considerations what general failure modes for tension members？ yielding in gross section fracture in effective net section block shear shear rupture along plane through the fasteners bearing on fastener holes prying what general failure modes for compression members？ yielding elastic/plastic global buckling local buckling,review,design details for columns choice of column section column construction beam-column connections beam cap connections column splices column bases bearing capacity analysis short column fai