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CIEG 301: Structural Analysis. INTRODUCTION Types of Structures Loads. Corresponding Reading. Chapter 1 of textbook. What Do Structural Engineers Do?. Analyze and design new structures Investigate the capacity and serviceability of existing structures
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CIEG 301:Structural Analysis INTRODUCTION Types of Structures Loads
Corresponding Reading • Chapter 1 of textbook
What Do Structural Engineers Do? • Analyze and design new structures • Investigate the capacity and serviceability of existing structures • Develop retrofit methods for existing structures with inadequate capacity • Forensic investigations • Research and development
Building Types • Majority of buildings are 2 – 20 stories • Taller office buildings • Sports arenas • Low seismic / high seismic
Bridge Types • Highway • Railroad • Shipping • Commuter • Pedestrian
Design Objectives • Strength • Constructability • Serviceability • Maintainability • Economy • Aesthetics
Design Process • Initial planning • Determination of design alternatives • Preliminary design of alternatives • Evaluation of alternatives • Design, analysis, and redesign of selected alternative • Construction
Structure Types • Frames • Trusses • Slab-on-stringer • Cables • Arches • Surface structures • Complex structures
Member Types • Each of these structures is comprised of hundreds or thousands of members • Some common member types • Beams / Girders / stringers - flexural members – load applied perpendicular to length, moment and shear are primary forces • Columns – compression members – load applied parallel to length at member ends, axial force dominates • Beam-columns • Tension members • Compression members • Tie rods – tension force only • Arches • Common connection types • Pinned • Fixed
Support Types • Roller • Pin • Fixed
How do we design structures? • Conceptual Consideration: • Determine forces (and deflections) • Our focus for the semester • Determine capacity (and deflection limits) • Focus in Structural Design next semester • Require capacity is greater than forces • Legal Considerations • For most structures, owner specifies code • e.g., AISC, PCI, AASHTO, AREMA
Loads • Forces in a structure are a result of loads • What types of loads do we need to consider in a civil engineering structure: • Dead load: • Live load: building occupants, truck traffic • Environmental loads: • Snow load • Rain load • Wind load • Seismic load • Bridge specific • Temperature loads (expansion and contraction of restrained members) • Impact • Breaking force • Collisions (water and land traffic) • Water loads • Ice
Dead Loads • Self-weight of: • Structural components (e.g., beams, slabs) • Non-structural components (e.g., decorative façade, plywood subfloor, ceiling tiles, asphalt wearing surface) • Useful Tables in textbook: • Table 1-2: Densities of Typical Materials • Table 1-3: Dead Loads of Typical Materials
Load Transfer and Load Distribution • Consider a typical building framing plan • Work from top down • Determine tributary widths and tributary areas as appropriate