Structure of a Building STRUCTURAL ENGINEERING Structure of a Building The primary function of a building structure is to support and transmit the loads and forces to the ground. “Tracing the Loads” or “Chasing the Loads”

Characteristics of a Structure Stability – needed to maintain shape. The structure is dependent upon balanced forces and equilibrium Strength - ability of the structure to withstand the applied forces, usually includes a “factor of safety” Economic Value – includes choices made about the design, materials, and function of the structure

Forces and Loads Design Loads Dead Loads (DL) –fixed loads building materials/components and the weight of structural components Live Loads (LL) –transient and moving loads Occupancy loads and furnishing loads (bldg usage) Snow loads Construction loads Live Load maybe variable during structures lifetime Building codes specify these loads for floor and roof loadings

Design Loads Snow Live Load Roof Materials & Structure Dead Load Walls, Floors, Materials &Structure Dead Load Occupants, Moveable Fixtures & Furniture Live Load

Design Loads (continued) WIND Wind Load (WL) – Resulting loads yields Lateral load on walls Downward and upward pressure on roofs Pressure Uplift Suction

Design Loads (continued) Earthquake Loads (EQ) Seismic load based on building mass , type and configuration. Vertical and lateral forces (dynamic) Building codes can simplify loading Epicenter Seismic Forces at Base of Building Hypocenter

Loads & Load Paths Snow or roof load for non-snow areas Use and occupancy Self weight of structure Ground reaction