Building Code Provisions

In April 2009 the BCBC introduced new provisions allowing the height of wood-framed structures to be increased from 4 storeys to 6. I have posted the link for anyone to look at and hopefully get a better idea of why the code has changed.

http://www.housing.gov.bc.ca/building/wood_frame/6storey_form.html

Shear Wall Design

WHAT ARE THE FUNCTIONS OF A SHEAR WALL?

• What are the two functions of a shear wall?
  • Strength and Stiffness

• The figure shows strength and stiffness
  • Strength
    • Shear walls must provide the necessary lateral strength to resist horizontal earthquake forces.
    • When shear walls are strong enough, they will transfer these horizontal forces to the next element in the load path below them, such as other shear walls, floors, foundation walls, slabs or footings.
  • Stiffness
    • Shear walls also provide lateral stiffness to prevent the roof or floor above from excessive side-sway.
    • When shear walls are stiff enough, they will prevent floor and roof framing members from moving off their supports.
    • Also, buildings that are sufficiently stiff will usually suffer less nonstructural damage.
    
    
    
    
    http://www.nrc-cnrc.gc.ca/eng/ibp/irc/ctus/ctus-n45.html

Quake Test

Proposed Research Topic: The Seismic Response of Mid-Rise Wood-Frame Construction

Purposes: In April of 2009 new provisions in the BC Building Code came into effect allowing the maximum height of residential wood-framed construction to increase from four storeys to six. Since British Columbia is located in an active seismic region of the world, concerns over the safety of structures during seismic events have been raised. Many people believe that during an earthquake a building that is constructed from steel and concrete would offer superior protection than a building that is constructed primarily of wood, however this is not the case. In this project, I will explore how the forces of seismic activity will affect a wood-framed structure. In particular, I will focus on the technical aspects of construction and why this type of building can withstand seismic activity and how much stress the overall building can withstand before total failure.

Background: Previous to this code change typical wood-frame construction was limited to four storeys. Past experience has shown that the code provisions have generally led to buildings that are safe. More recently, material codes have shifted to reliability based design to increase the uniformity of safety for all building materials. But little is known about the seismic effects on these structures. For this reason I will be conducting my research using the help of engineers and other various sources. With the help of these professionals I will provide specifications and standards for sheathing, lumber, fasteners, light gauge steel connectors, hold-downs and anchor bolts, and show details of lateral shear, and show details of shearwall construction. The shearwall will be the main component under the most scrutiny because of its ability to withstand the lateral forces that are associated with seismic activity.

Objectives: I will be using data gathered from the above methods to determine whether mid-rise wood-frame construction is feasible in seismically active regions of the world, not just British Columbia. Part of my research will allow me to determine the seismic effects on the structure and if the building can withstand multiple earthquakes. I will be meeting regularly with structural engineers who will assist me in my studies. Hopefully I will be able to attend some strength tests and participate in some of the design process to achieve better understanding of the forces at work on a wood-frame structure. Interviews and meetings will also be conducted during a bi-monthly basis to further my knowledge in my area of study. However I will be conducting most of my research independently.

Theoretical framework: I will be guided most generally by the BC Building Code and other related sources. Since mid-rise wood-frame construction is a relatively new concept I will be exploring key areas of the code such as part 3 and 4 and seismic data. Using the data provided by these sources and the help of engineers I can find sufficient data that will prove whether or not mid-rise wood-frame construction is a good idea in seismic regions of the world.

Method:

1. Conduct a literature review on wood-frame construction, seismic activity and structural

engineering.

2. Meet with a structural engineer on bi-monthly basis to observe the engineering methods that

are used to design wood-framed structures and how forces and load calculations are applied to

the building model. I will spend about 2 hours each meeting to gather the necessary information

needed.

3. Attend structural testing and interview structural engineers to clarify and provide insight into

the test that is occurring. I will attempt to conduct these interviews while the tests are in

progress. While the interviews will not be formal or structured, the kinds of questions I will ask

include the following.

a. Tell me about the test that is about to happen?

b. What result are you looking for in this test?

c. What do you think will happen during the test based on your calculations?

d. What is this test accomplishing?

e. What happens if the test fails?

f. What happens if the test is a success?

g. Would this be a practical design if the test passes?

e. How do you feel about this test?

4. Undertake a situational analysis of the information and data that I have gathered.

5. Write a research report that will determine whether mid-rise wood-framed construction is a

good building tactic in seismic regions.

Timetable:

Prepare proposal by 1 February

Complete literature review by Spring 2010

Complete fieldwork by Summer 2010

Complete analysis by Fall 2010

Give presentation on Fall 2010

Complete final report by Winter 2011

Limitations: Time constraints of the semester require less time than may be ideal for a complete structural analysis. By being with an engineer four hours a month for four months, there are bound to be aspects of structural design and engineering that will not be covered in my initial research. Being an outsider with little engineering experience may also limit what is revealed to me. The engineers may be secretive in their conversations around me, especially in my initial observations.

Welcome!

Hey everybody, welcome to my Blog! So im making this blog because I have to write a technical report, my topic is The Seismic Response of Mid-Rise Wood-Frame Construction. So im looking to get some feedback from my classmates and any other people who would like to offer their ideas.