STRUCTURAL ENGINEERING - PowerPoint PPT Presentation

Loading...

PPT – STRUCTURAL ENGINEERING PowerPoint presentation | free to view - id: 7b1195-MmU3Y



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

STRUCTURAL ENGINEERING

Description:

structural engineering – PowerPoint PPT presentation

Number of Views:161
Avg rating:3.0/5.0
Slides: 52
Provided by: johns326
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: STRUCTURAL ENGINEERING


1
STRUCTURAL ENGINEERING

2
What Does a Structural Engineer Do?
3
What Does a Structural Engineer Do?
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
Roles of a Structural Engineer
  • Lead engineer/Project engineer
  • Consultant for an architect
  • Consultant for another engineer, insurance
    companies, lawyers, etc.
  • As well as
  • Aerospace design.
  • Product design, etc. for industries.
  • Facilities engineer.

8
Lead or Project Engineer
  • Defines project goals
  • Costs
  • Performance requirements
  • Supervises design based on these requirements.
  • Outlines tasks
  • What needs to be done who will do it
  • Organizes Project
  • Calendar
  • Sequence

9
Palm Valley Interchange
10
(No Transcript)
11
(No Transcript)
12
Lower Granite Dam Lock Repair Jarrod Milligan
13
(No Transcript)
14
Consulting for an Architect or Engineer
  • The architect works with the client to establish
    project requirements
  • space requirements and relationships
  • siting
  • aesthetics
  • lighting
  • budget

15
Consulting for an Architect or Engineer
  • The engineers job is to make the architect look
    good.
  • Ensure integrity of structure
  • Provide economical solutions.
  • Develop innovative ways to solve new problems and
    use new materials.

16
Boise Air Terminal
17
(No Transcript)
18
(No Transcript)
19
Forensic Engineering
  • Finding out what went wrong.
  • Insurance companies
  • Lawyers

20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
Design Loads
  • Design loads include
  • Dead loads
  • Self-weight,
  • Permanent contents.
  • Live loads
  • Occupants,
  • Transient contents
  • Environmental loads
  • Wind, snow, earthquake, etc.

24
Uncertainty
  • Dead loads can be predicted with some confidence.
  • Live load and environmental load predictions are
    much more uncertain.
  • E.g., it is nearly impossible to say what will be
    the exact maximum occupancy live load in, say, a
    classroom.
  • It is also difficult to say how that load will be
    distributed in the room.

25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
Uncertainty (cont.)
  • Structural codes account for this uncertainty two
    ways
  • We chose a conservative estimate (LARGE estimate)
    for the load
  • E.g., a 50-year wind load, which is a wind load
    that occurs, on average, only once in 50 years.
  • We factor that estimate upwards just to be sure.

29
Load Factors
  • Newer codes have separate load and resistance
    factors
  • Load factors overestimate the load.
  • Resistance factors underestimate the strength
    of the structure.
  • Dead load factors range from 1.1 to 1.4
  • Smaller uncertainty.
  • Environmental and live load factors range from
    1.7 to 2.0 and higher.
  • Higher uncertainty

30
Simplified Wind Loads
  • Since we cant predict exactly the maximum load a
    given structure will experience, the code
    provides
  • Rational procedures for estimating a reasonable
    maximum value
  • Procedures for arranging the loads on the
    structure.
  • Experience has shown that if the engineer follows
    these procedures he/she can expect the structure
    to perform properly (i.e., not collapse, etc.)

31
Wind Loads
  • What factors should the wind design loads
    consider?

32
Summary
  • Design loads used by engineers represent rational
    estimates of loads that we should consider in our
    design.
  • Experience has shown if we design for these
    loads, the building should survive for a
    reasonable amount of time (50 years or more).

33
Summary (cont.)
  • The models try to consider situations that will
    have a significant effect on the design load.
  • Max wind speed, building height and shape, etc.
  • The maximum loads estimated by the design codes
    are then factored to add a safety margin to our
    calculations.

34
Example Building
35
Design Methods
  • Method 1 Simplified Procedure
  • Simple diaphragm building,
  • Low-rise,
  • Enclosed,
  • Regular geometry, symmetric,
  • Not flexible, prone to flutter/vortex shedding,
    torsion etc.
  • Method 2 Analytic Procedure.
  • Method 3 Wind Tunnel Procedure.

36
Wind Loads on Structures
37
Gust Factor, G
  • G 0.85 for rigid, low rise buildings

38
Wall Pressure Coefficients, Cp
39
Wind Velocity Pressure
40
Importance Factor
  • Agriculture Buildings Category I
  • Typical Buildings Category II
  • Hazardous Buildings Category III
  • Essential Facilities Category IV

41
Wind Load Map Western US
Wind speeds in MPH (kph)
42
Velocity Pressure Exposure Coefficients
Exposure B, Case 2
43
Velocity Pressure Exposure Coefficients Notes
  • Case 1
  • a. All components and cladding.
  • b. Main wind force resisting system in low-rise
    structure designed using Figure 6-10 Method 2.
  • Case 2
  • a. All main force wind resisting systems in
    buildings except those in low-rise buildings
    designed using Figure 6-10.
  • b. All main wind force resisting systems in other
    structures.
  • We will use Case 2.

44
Velocity Pressure Exposure Coefficients (cont.)
45
Exposure Categories
  • Exposure B
  • Urban and suburban areas, wooded areas Exposure
    B shall be assumed unless the site meets the
    definition of another type of exposure.
  • Exposure C
  • Open terrain with scattered obstructions
  • Exposure D
  • Flat unobstructed areas exposed to wind flowing
    over open water for a distance of at least one
    mile

46
Directionality Factor Kd
47
Topographic Factor Kzt
If flat terrain Kzt 1
48
Wind Loads
  • Calculate Wind Loads
  • Wind From East
  • Wind From West

49
(No Transcript)
50
(No Transcript)
51
(No Transcript)
About PowerShow.com