HomeMy WebLinkAbout09052002 BSC Agenda Item 10 • •
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City of West University Place•Texas
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Memo 1 ' y
To: Building Standards Commission Members
From: Dennis Mack, Building Offici
Date: September 5,2002
Re: Motion by BSC
At the regular meeting of the Building Standards Commission on August 1,2002 Les Albin
made a motion to request staff to develop a procedure to have all foundation and structural
plans reviewed by an independent Engineer licensed in the state of Texas. This motion was
passed by a 3 to 2 affirmative vote.
Commissioners,as you may remember this same request and recommendation on behalf of
the BSC was reviewed by the city council back in April of this year. Staffs position on this
matter was presented to City Council in the form of a memo that I had prepared on April 15,
2002 (see attached) and addressed to Michael Ross,who at that time was our Assistant City
Manager/Director of Public Works.
In view of the fact City Council denied BSC's request on this subject I see no reason to
change my position on this matter.Therefore I would like to thank the BSC for their request
and concerns on this issue,but at this time I respectfully decline their request as well.
PC: City Manager
Assistant City Manager/Director Public Works
City of West University Place•Texas
Memo
To: Michael Ross
Assistant City Manager/ Director of Public Works
From: Dennis Mack,Chief Building Official
Date: April 15,2002
Re: Foundations
The Building Standards Commission is of the opinion the city has experienced excessive
failure of residential foundations due to improper designs by Professional Engineers.As a
result of this belief they have made a request that the city council discuss the possibility of
requiring the city to hire a consulting engineer to review the engineering of foundation plans
submitted for permits.
It is my opinion the city should not proceed with this proposal for the following reasons.
1. The belief the city has experienced excessive foundation failure due to improper
designs by professional engineers is not backed by any methodical study by a
Forensic engineer but was simply a conclusion reached by counting the number of
foundation repair permits issued by the city in a one or two year period.There was
no attempt to establish the cause of foundation failure within the city,nor was their
any attempt to authenticate the number of repair permits constituted an excessive
percentage of foundation failures for this region of the state.The City of West
University Place as well as the surrounding communities is largely made up of
areas with clayey soils that shrink and swell with changes in soil moisture content.
This shrinking and swelling may cause movement of residential foundations that
adversely affects the residence. Other factors may influence foundation
performance as well. Some of these factors are inadequate construction,the degree
of compaction of the supporting soils,landscaping practices,leaking plumbing, and
drainage slope instability.
2. Addressing the cause or causes of foundation movement may preclude the need for
structural repairs or reduce the risk of continuing foundation movement after
structural repairs. Implementing non-structural recommendations and monitoring
foundation performance prior to implementing structural repairs may be a prudent
approach,provided it is cost effective and the owner is willing to allow time to
foundations.doc
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measure the effects of such measures. Some of these non-structural remedial
measures are as follows:
a. Vegetation Alteration. Trees or large shrubs near the foundation cause or
could potentially cause soil shrinkage under the foundation. Removal of
these trees or shrubs may prevent soil shrinkage and may even result in at
least partial restoration of settled areas of the foundation. Removal may,
however,result in foundation upheaval due to soil moisture increase or
settlement due to root decay. If the trees and shrubs pre-date the structure,
pruning of tree branches may be a more prudent approach.
b. Root Barriers. If pruning tree roots is not either effective or practical,a
root barrier can often mitigate the effects of the tree(s)by limiting root
growth under the foundation. Root barriers generally consist of a vertical
barrier of low grade concrete,Plexiglas,sheet metal,chemically treated
geo-fabric or other appropriate material.
c. Gutters and Downspouts. The absence of roof guttering around a
structure can cause both erosion and the ponding of water near the structure.
If either of these conditions is present,the addition of gutters and
downspouts should be installed. Downspouts should be of adequate size to
drain roof runoff during typical storms. Extending downspouts at least 5
feet past the edge of the foundation and past the edge of all planting beds is
recommended.
d. Drainage Improvements. Since foundation movement in expansive soils
is related to soil moisture content,it is important to maintain positive
drainage away from the foundation to reduce the risk of foundation
upheaval. Drainage improvements are appropriate both to address existing
upward foundation movement and as preventative measures.
e. Surface Grading. Performance based surface grading should be followed
that insure the generally desired flow direction is maintained and the
requirement that water ponding near the foundation be followed. A
minimum slope of 5% (e.g. 5 feet in 100 feet) away from the foundation for
at least 5 feet and 2% (e.g. 2 feet in 100 feet) along any swale is
recommended.
f. Erosion Control. Added soil should have adequate clay content to
minimize water movement through the added soil. Retaining structures of
significant height should be designed using appropriate soil and structural
parameters. The slope should not exceed 15%to minimize erosion yet
provide drainage.
g. Surface Water Drainage Systems. When inadequate slope exists to
provide surface drainage by grading alone,underground drainage systems
should be installed. These systems typically consist of one or more
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drainage inlets connected to a solid(not perforated)piping system. If
possible,the system should drain by gravity. Otherwise,it may be
necessary to include a sump pump in the system. The ground surface
should be graded to slope to the drainage inlets. As long as the pipe is of
sufficient size,downspouts in the area may be connected to the drain
system. Cleanouts should be included for maintenance of the system.
h. Subsurface Water Drainage Systems. Shallow(sometimes "perched")
subsurface water can cause soil-swelling resulting in foundation upheaval.
This condition can often be mitigated by the installation of a subsurface
water drainage system,often referred to as a"French"drain. Although a
true"French"drain is simply a trench filled with clean stone or gravel,
subsurface water drainage systems usually should include a perforated pipe
at the bottom of the trench and a geotextile around the pipe and/or the
aggregate in the trench to prevent fine-grained soils from reducing the
effectiveness of the drain system. Cleanouts for maintenance of the system
should be included. Gutters and downspouts should not be connected to this
type of drain system.
i. Moisture Barriers. Moisture barriers have been effectively used when
migration of moisture under the foundation has either occurred or is
anticipated. Moisture barriers can be either vertical or horizontal,but
vertical moisture barriers are believed to be more effective,depending on
the depth to which they are installed. Moisture barriers generally consist of
impermeable plastic sheeting or other appropriate material that is attached
to the edge of the foundation. Moisture barriers can be used in conjunction
with Root Barriers and/or Subsurface Water Drainage Systems.
3. If the city hires a professional engineer to check another professional engineer's
work and corrections are made as a result of this review the city may open itself up
for future liability. Some of the sections of the Texas Engineering Practice Act that
concern me the most are as follows:
§131.152. Engineers Shall Be Objective and Truthful.
(e) Engineers shall only issue work conforming with the board's sealing rules. However,an engineer,as a third party,may
alter,complete,correct,revise,or add to the work of another engineer when engaged to do so by a client,provided:
(1)the client furnishes the documentation of such work submitted to the client by the first engineer;
(2) the first engineer is notified in writing by the second engineer of the engagement immediately upon acceptance of the
engagement;and
(3) any work altered, completed, corrected, revised, or added to shall have a seal affixed by the second engineer. The
second engineer then becomes responsible for any alterations, additions or deletions to the original design including
any effect or impact of those changes on the original engineer's design.
§131.155. Engineers' Responsibility to the Profession.
(c)The engineer shall not:
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(2) maliciously injure or attempt to injure or damage the personal or professional reputation of another by any means.
This does not preclude an engineer from giving a frank but private appraisal of engineers or other persons or firms
when requested by a client or prospective employer;
§131.166. Engineers'Seals.
(a) The purpose of the engineer's seal is to assure the user of the engineering product that the work has been performed
by the professional engineer named and to delineate the scope of the engineer's work.The engineer shall utilize the
designation "P.E." or the titles set forth in the Texas Engineering Practice Act (Act), §1.3. Physical seals of two
different sizes will be acceptable: a pocket seal (the size commercially designated as 1-5/8-inch seal) or desk seal
(commercially designated as a 2-inch seal)to be of the design shown in this subsection. Computer-generated seals
may be of a reduced size provided that the engineer's name and number are clearly legible.
(k) Work performed by more than one engineer shall be sealed in a manner such that all engineering can be clearly
attributed to the responsible engineer or engineers. When sealing plans or documents on which two or more
engineers have worked,the seal of each engineer shall be placed on the plan or document with a notation describing
the work done under each engineer's responsible charge.
(I) Licensed employees of the state, its political subdivisions, or other public entities are responsible for sealing their
original engineering work; however, such licensed employees engaged in review and evaluation for compliance
with applicable law or regulation of engineering work submitted by others,or in the preparation of general planning
documents, a proposal for decision in a contested case or any similar position statement resulting from a
compliance review, need not seal the review reports, planning documents, proposals for decision, or position
statements.
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