BRIDGE ARCHITECTURE
I
T is quite generally agreed that there is a bridge architecture. Its place in bridge construction has not been clearly defined. Of late years the subject has been discussed more as to who should be in responsible charge of bridge design—architects or engineers. This cannot be determined without some clearly defined limitations as to what constitutes bridge architecture. Of the several points to be considered, there are included (1) what constitutes a bridge, (2) the elements of bridge design, (3) the limitations of architecture and engineering, (4) competency for bridge designing.
A bridge (1) may be defined as a structure which is self-supporting between two points of support and includes a thoroughfare. It may consist of one or more spans. The types generally used are the framed truss, cantilever, suspension, girder and arch. They are generally constructed of steel, the girder and arch may be made of concrete and the arch of stone. Framed bridges may be made also of a combination of wood and steel.
The elements of a bridge (2) consist of the foundations ; piers, columns or abutments that support the span ends; the span structure; the thorough
fare floor system and anchorage for suspension bridge cables. These parts are proportioned to support the traffic loads, the dead weight of the structure, to resist stresses induced by wind, Hood and ice and flotation. They are also proportioned to comply with predetermined general conditions, such as dimensions of span, widths, elevations, supporting soil and traffic. The designing as a simple structure must conform to certain established practice and formulas. The practical experience, skill and judgment of the designer make possible economies in design and erection. Economical design, reduced to the utmost limit should be one of the factors. The study of the problem for appearance should be undertaken at the conception of the project. It is understood that economical design includes the characteristics of stability and durability. These elements of bridge design are ordinarily of a purely engineering character.
The limitations of architecture and engineering (3) naturally are fixed by the nature of the two arts. Engineering is usually confined to the elements already described (2). Complying with mechanical laws they often possess beauty. Curves in a suspension bridge, such as the catenary and
WASHINGTON MEMORIAL BRIDGE, WILMINGTON, DEL.
VANCE W. TORBERT, ARCHITECT—BENJAMIN H. DAVIS, ENGINEER
I
T is quite generally agreed that there is a bridge architecture. Its place in bridge construction has not been clearly defined. Of late years the subject has been discussed more as to who should be in responsible charge of bridge design—architects or engineers. This cannot be determined without some clearly defined limitations as to what constitutes bridge architecture. Of the several points to be considered, there are included (1) what constitutes a bridge, (2) the elements of bridge design, (3) the limitations of architecture and engineering, (4) competency for bridge designing.
A bridge (1) may be defined as a structure which is self-supporting between two points of support and includes a thoroughfare. It may consist of one or more spans. The types generally used are the framed truss, cantilever, suspension, girder and arch. They are generally constructed of steel, the girder and arch may be made of concrete and the arch of stone. Framed bridges may be made also of a combination of wood and steel.
The elements of a bridge (2) consist of the foundations ; piers, columns or abutments that support the span ends; the span structure; the thorough
fare floor system and anchorage for suspension bridge cables. These parts are proportioned to support the traffic loads, the dead weight of the structure, to resist stresses induced by wind, Hood and ice and flotation. They are also proportioned to comply with predetermined general conditions, such as dimensions of span, widths, elevations, supporting soil and traffic. The designing as a simple structure must conform to certain established practice and formulas. The practical experience, skill and judgment of the designer make possible economies in design and erection. Economical design, reduced to the utmost limit should be one of the factors. The study of the problem for appearance should be undertaken at the conception of the project. It is understood that economical design includes the characteristics of stability and durability. These elements of bridge design are ordinarily of a purely engineering character.
The limitations of architecture and engineering (3) naturally are fixed by the nature of the two arts. Engineering is usually confined to the elements already described (2). Complying with mechanical laws they often possess beauty. Curves in a suspension bridge, such as the catenary and
WASHINGTON MEMORIAL BRIDGE, WILMINGTON, DEL.
VANCE W. TORBERT, ARCHITECT—BENJAMIN H. DAVIS, ENGINEER