Fig. 13a. Layout for 1,700-Foot-Span, Cantilever, Railway Bridge 95

Fig. 13b. Layout for 1,700-Foot-Span, Suspension, Railway Bridge 95

Fig. 13c. Cost-Curves for Double-Track-Railway Bridges . . 96

Fig. 13d. Layout for 2,400-Foot-Span, Cantilever, Railway Bridge 97

Fig. 13e. Layout for 2,400-Foot-Span, Suspension, Railway Bridge 98

Fig. 13f. Modified Cost-Curves for Double-Track-Railway Bridges 99

Fig. 13g. Dr. Steinman's Layouts for Cantilever Bridges 101

Fig. 13h. Dr. Steinman's Layouts for Suspension Bridges 101

Fig. 13i. Cost-Curves for Combined Railway and Highway Bridges

of the General Type Computed by Dr. Steinman 105

Fig. 13j. Cost-Curves for Highway Bridges of Carbon Steel . . . . 107

Fig. 13k. Diagram of Main-Span-Lengths of Equal Cost for

Combined-Railway-and-Highway, Cantilever and Suspension

Bridges 109

CHAPTER XVII

ECONOMICS OF TIME AND MONEY IN MAKING COST-
ESTIMATES FOR BRIDGES

Fig. 17a. Profile for Student Problem No. 1 . facing p. 148

Fig. 17b. Profile for Student Problem No. 2 . facing p. 148

Fig. 17c. Profile for Student Problem No. 3 . facing p. 148

Fig. 17d. Profile for Student Problem No. 4 . facing p. 148

CHAPTER XVIII

ECONOMIC SPAN-LENGTHS FOR SIMPLE-TRUSS BRIDGES ON
VARIOUS TYPES OF FOUNDATION

Fig. 18a. Live-Plus-Impact Loads . . . 153

Fig. 18b. Live Loads without Impact 154

Fig. 18c. Total Weights of Metal in Superstructures 155

Fig. 18d. Costs per Lineal Foot of Structure for Low-Level,

Combined Bridges on Sand Foundations 100 Feet Deep 159

Fig. 18e. Costs per Lineal Foot of Structure for Low-Level,

Combined Bridges on Sand Foundations 150 Feet Deep 161

Fig. 18f. Costs per Lineal Foot of Structure for Low-Level,

Combined Bridges on Sand Foundations 200 Feet Deep 162

Fig. 18g. Costs per Lineal Foot of Structure for Low-Level,

Combined Bridges on Sand Foundations 250 Feet Deep 163

Fig. 18h. Economic Span-Lengths for Simple-Truss Bridges on

Various Types of Foundation 164

Fig. 18i. Diagram of Weight-Ratios showing Effect of Lengthening

the Central Span of any Simple-Truss, Three-Span Layout,

Keeping the Total Length Unchanged 166

CHAPTER XX

ECONOMICS OF TRUSSES AND GIRDERS

Fig. 20a. Economic Depths of Plate-Girders with Riveted End-Connections . . 180