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TYPES OF LOADS IN STRUCTURES Prepared by 1. Anmar Hisham Ali Al-Hanawi 423104825 2. Abdulaziz Al-sheri 424101567 3. Abdulelelah M. Abu-Shaatat 424101577 Supervised by: Dr. Shehab Mourad Structural Loads A load may be defined as a force tending to effect and produce deformations, stresses or displacements in the structure. Types of Loads in Structures Dead loads. Live loads. Dynamic loads. Wind loads. Earthquake loads. Snow loads. Dead Loads Weight of the structure. Floors, Beams, Roofs. Loads that are “always there” Live Loads Loads that may move or change mass or weight: for example: People, furniture, equipment. Minimum design loadings are usually specified in the building codes. Example of Live Load Ballroom Live Load = 100 N/mm^2 Dynamic Loads Moving loads (e.g. traffic) Impact loads Gusts of wind Loads due to cycling machinery Load Example - water in a dam Water, ρ = density h P = ρgh Earthquake Loads Structure loaded when base is shaken. Response of structure is dependent on the frequency of motion. Gravity Load Lateral Load Wind load Uniformly increasing Load Snow load Lateral Load Seismic load Wind Loads The amount of wind load is dependent on the following: • Geographical location, • The height of structure, • Type of surrounding physical environment, • The shape of structure, • Size of the building. Snow Loads The amount of snow load on a roof structure is dependent on a variety of factors: • Roof geometry, • Size of the structure, • Insulation of the structure, • Wind frequency, • Snow duration, • Geographical location of the structure. Loads Acting in Structures Vertical: Gravity Lateral: Wind, Earthquake Global Stability Sliding Overturning Forces in Structural Elements 100 lb 100 lb Tension Compression Forces in Structural Elements 100 lb Bending Torsion Typical Structural Systems Arch Typical Structural Systems Truss C T C C T Forces in Truss Members Typical Structural Systems Frame Typical Structural Systems Force Beam Displacement Types of Structural Elements - Beams Loads Compression Tension Force Transfer from Beams to Supports Force, P 2/3 P 1/3 L 2/3 L Span, L 1/3 P Force Transfer Example - Bridge 8,000 lb 32,000 lb 15 ft 45 ft 30 ft 30 ft L = 60 ft 22,000 lb 18,000 lb Load Representation Concentrated Load (Point Load) Uniformly Distributed Load (UDL) wL w P L Uniformly Increasing Load wL/2 Area Load w w 1/3L 1/3L 1/3L L 5
