Avoiding Falsework Failure
Eugene G. Washington, P.E.
This course will
discuss the design considerations of bridge falsework and the causes of failure
as each element of the falsework system is discussed. The principals of falsework
design apply to any temporary structural system designed to support the weight
of a permanent structure during erection and until the permanent structure is
self supporting. Post-tensioned box girder bridge falsework is selected for
discussion because it can contain all of the complications that can result in
structural failure. Bridge falsework often must span traffic, rivers and safely
support massive weights in adverse conditions.
This course includes a True-False quiz at the end, which is designed to enhance the understanding of the course materials.
purpose of this course is to lead the reader through each design step and discuss
the various failures that can occur in each element. Once the reader understands
all the detail required to successfully design, erect and strip falsework, most
causes of failure can be easily eliminated.
I am sure falsework
failures have plagued builders since the first Roman arch construction. Even
today there are occasionally falsework collapses that cause human and economic
disaster. Most of these failures are easily preventable. Falsework failure includes
excessive settlement, deflection and crushing as well as the catastrophic collapse.
Some are the result of an unexpected natural event such as a flood, storm winds,
or earthquake. Most falsework failures are the result of human error. An error
in calculation, or failure to consider the way the construction loads are introduced.
Poor quality of materials, improper substitution of material, inattentive crews
and lack of attention to detail all can result in disaster. We will discuss
many of these causes as the course continues.
The course content is in a PDF file Avoiding Falsework Failure. You need to open or download this document to study this course.
Any number of reasons
or combination of missteps can cause excessive settlement or collapse. Every
structural member is critical to the integrity of the entire falsework system.
An experienced engineer should make a thorough review the design and then make
a detailed inspection before any bridge rebar or concrete is placed. Other than
Acts of God all falsework failures are the result of human error. The only way
to ensure a safe falsework is attention to every detail and insistence on competent
installation. Many falsework collapses occur during the stripping operations,
so the falsework must be designed to be safely dismantled and monitored for
adherence to proper procedures.
1. Building Code
Requirements for Structural Concrete (ACI 318-95)
2. Manual of Steel Construction - Allowable Stress Design, 9th edition by AISC
3. Fundamentals of Soil Mechanics, Feb 1965 by Donald W. Taylor
4. Reinforced Concrete Design, 1965 by Chu-Kia Wang and Charles G. Salmon
5. The Encyclopedia of Applied Geology, 1984 edited by Charles W. Finkl, Jnr.
6. Handbook of Hydraulics, 1976 by Ernest F. Bater and Horace Williams King
7. Handbook of Heavy Construction, 2nd edition, 1971 Edited by John A. Havers and Frank W. Stubbs, Jr. Concrete Manual, 1981 US Bureau of Reclamation
8. California falsework manual - division of structures, Dept. of Transportation, latest edition
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.