A structural member that spans horizontally between supports that develop inwardly directed horizontal reactions when the member is subjected to a vertical load. The member axis is usually curved and usually lies in a vertical plane. Arches are used to support decks for roadways, railroad tracks, and pipelines on bridges, as well as in buildings to support walls, floors, and roofs in order to provide spaces unobstructed by columns. They may be built of steel, concrete (plain, reinforced, or prestressed), composite concrete-steel, timber, or masonry. See also: Structural materials

A bridge with vertically curved compression-dominant members spanning an opening to support moving loads; it is the oldest bridge type. An arch bridge over a deep valley is beautiful and has no competitor as far as aesthetics are concerned.

The science of sound as it pertains to buildings. There are three major branches of architectural acoustics. (1) Room acoustics involves the design of the interior of buildings to project reflected and diffused sound at appropriate levels and time intervals and with appropriate esthetic qualities for music and adequate intelligibility for speech. Room acoustics is an essential component of the design of theaters, concert halls, lecture rooms, classrooms, and churches, among other building types. (2) Noise control or noise management involves the reduction and control of noise between a potentially disturbing sound source and a listener. The walls, floors, ceilings, windows, and doors in buildings reduce sound energy as it travels through them. Sources of disturbing noise may be equipment and people within the building or intruding noise from external sources of sound, such as amplified music, airplanes, or highways. Noise from building services, including heating, ventilating, and air-conditioning systems; lighting systems; communication, voice, and data systems; and electric power systems, must also be controlled so that it does not disturb people using the buildings. (3) The design of sound reinforcement and enhancement systems uses electronic equipment to improve the quality of the sounds heard in rooms.

A discipline that deals with the technological aspects of buildings, including the properties and behavior of building materials and components, foundation design, structural analysis and design, environmental system analysis and design, construction management, and building operation. Architectural engineering can also be called building engineering. The scope of the field is vast, broadly encompassing structural, mechanical, environmental, climate control, electrical, and lighting aspects of buildings (see figure), as well as security and telecommunications, and extending even further to aesthetics and ergonomics. See also: Buildings; Foundation; Structural analysis; Structural connections; Structural design; Structural engineering; Structural materials; Structural mechanics; Structural stability; Structure (engineering)

An integrated arrangement of fixed facilities for protection from combustion by use of water extinguishment. The system comprises an adequate water supply, hydraulically designed internal piping, and sprinklers connected in a systematic pattern over the protected area; the system is activated by a fire to discharge a fine spray of water over the heat.

A structural member that is fabricated from metal, reinforced or prestressed concrete, wood, fiber-reinforced plastic, or other construction materials and that resists loads perpendicular to its longitudinal axis. A beam's length is usually much larger than its depth or width (Fig. 1). Usually beams are of symmetric cross section; they are designed to bend in this plane of symmetry, which is also the plane of their greatest strength and stiffness. This plane coincides with the plane of the applied loads.

A beam-column is a structural member that is subjected to axial compression and transverse bending at the same time. The combined compression and bending may be produced by an eccentrically applied axial load (Fig. 1a), a concentrically applied axial load and one or two end moments (Fig. 1b), oran axial load and a transverse load between the two ends (Fig. 1c), or a combination of all three. A beam-column differs from a column only by the presence of the eccentricity of the load application, end moment, or transverse load.

A construction material usually made of clay (or shale) and extruded or molded as a rectangular block. Three types of clay are used in the manufacture of bricks: surface clay, fire clay, and shale. Adobe brick is a sun-dried molded mix of clay, straw, and water, manufactured mainly in Mexico and some southern regions of the United States. See also: Clay; Clay, commercial

A structure that provides smooth and safe passage over a valley, road, body of water, or other obstruction. Many types of bridges have been built and are classified based on their intended use, the materials used, and their structural design (Fig. 1).

Project management and construction operations involved in the building of a bridge. A fundamental part of construction engineering is construction project management (such as project design, planning, scheduling, and controlling). Some major bridge projects may provide an opportunity for contractors to submit a value-engineering recommendation to increase the value of the finished project while reducing the amount spent or invested; in other words, to provide the desired functions for minimum cost. Bridge construction technology has been evolving with industrial innovation and invention of new materials. The final aim of bridge construction is to build a high-quality bridge in accordance with the construction documents at minimum cost (see Illustration). See also: Bridge; Bridge design; Construction engineering; Construction methods; Engineering and architectural contracts; Value engineering