Distinct from many undergraduate textbooks, which are focused mainly on either teaching manual analysis methods and applying them to simple, idealized structures or reformulating structural analysis methods in terms of matrix notation, this text instead encourages the student to develop intuition about structural behavior. The authors of this text recognize the notion that engineers reason about behavior using simple models and intuition they acquire through problem solving. The approach adopted in this text develops this type of intuition by presenting extensive, realistic problems and case studies together with computer simulation, which allows rapid exploration of how a structure responds to changes in geometry and physical parameters.

bending, influence lines, force envelopes, and symmetry properties. We find it convenient from a pedagogical perspective to concentrate the related material in one location. It is also convenient for the reader since now there is a single source point for knowledge about each structural type rather than having the knowledge distributed throughout the text. We start with trusses since they involve the least amount of theory. The material on frames is based on beam theory so it is logical to

g f P1 > P2 F ab c max e d P2 > P1 = P1+P2(1−0.5 h ) l F ab max = P2+P1(1−0.5 h ) l Ffg 1.0 h d g f e f e d Faf + 2 2 h − 2 4 g d Fig. 2.28 (a) Influence line for cord member ab. (b) Vehicle positioning for Fab jmax . (c) Influence line for chord member fg. (d) Influence line for diagonal member af. (e) Influence line for diagonal member cf. (f) Uniform unit load 122 2 Statically Determinate Truss Structures e Fcf + 2 2 e − 2 4 h g f f −2 a d −2 b √2 3 2

¼ 1.0 dFu dFv 1.18 –1.09 0.00 0.59 0.82 –1.13 dFw F‘ AE 0.18 0.25 0.69 0.160 –0.165 –0.039 (in) alDT (in) 0.154 0.143 0.118 The displacements due to loads are u¼ X Fl dFu ¼ ð0:160Þð1:18Þ þ ðÀ0:165ÞðÀ1:09Þ ¼ 0:37 in: AE X Fl dFv ¼ ð0:160Þð0:59Þ þ ðÀ0:165Þð0:82Þ þ ðÀ0:039ÞðÀ1:13Þ AE ¼ 0:0032 in: v¼ X Fl dFw ¼ ð0:160Þð0:18Þ þ ðÀ0:165Þð0:25Þ þ ðÀ0:039Þð0:69Þ AE ¼ À0:0394 in: w¼ A 55 F temperature increase produces the following displacements: u¼ v¼ X w¼ X ða DTlÞ dFu ¼

of virtual forces to determine the horizontal and vertical displacement at joint b due to: (a) Loading shown. (b) Temperature increase of DT ¼ 16 C for members ab and bc. A ¼ 900 mm2 E ¼ 200 GPa a ¼ 12 Â 10À6 = C 2.8 Problems 173 30 kN 20 kN b 4m d 4m a c 5m 5m Problem 2.24 Use the principal of virtual force method to determine the horizontal component of the displacement at joint d. Assume A ¼ 0:5 in:2 and E ¼ 29,000 ksi. (i) For the loading shown (ii) For a fabrication of error of

. . . . . . . . . .. . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . 550 554 565 575 587 587 587 Vertical Retaining Wall Structures . .. . .. . .. . .. .. . .. . .. . .. . .. . .. . .. .. . .. . 8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.1 Types of Retaining Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.1.2 Gravity Walls .