Underground Construction - May 2020 - 40

CIGMAT 2020 Convention Review
Atul Hannan, director of the Planning
Division of Harris County Flood Control,
discussed using advanced technology for
better modeling and risk mapping.
There are many hydrologic and
hydraulic models, ranging from simple
to complex, steady state, unsteady state
and 2D models. Modelers have to select
the appropriate software, based on the
condition of the study site and the level
of analysis, professional experience and
cost, so they can understand the extent of
ﬂooding and map the ﬂoodplain or risk,
accordingly.
Hannan presented two complex ﬂooding problems modeled and mapped using
1D/2D model and compared with the
eﬀective maps. These advanced models
give lot of extra information about depth,
vector ﬂow, and conveyance zone, for
making better decision.

Kevin Tran, city of Houston; and Michael
Salinas and Michael Liga from Lockwood
Andrew and Newnam Inc., discussed
options for constructing 5,000 linear feet
(LF) of a 41,000 LF large diameter (120
to 54 inches) potable water pipeline via
tunneling for the city of Houston.
These include open-face tunnel construction, which is typically performed
when cohesive soils exist at the tunnel face
and immediately surrounding the bore
area, and groundwater can be controlled.
A tunnel boring machine (TBM) with face
closure abilities is recommended where
non-cohesive soils are present or mitigation of settlement is critical, and groundwater can be adequately controlled.
A pressurized face TBM may be required
where saturated, non-cohesive soils are
encountered in the tunnel zone and
dewatering is expected to be diﬃcult or not

possible. Subsurface chemical treatment
to stabilize the insitu soil is also an option
to create a suitable stratum for tunneling
operations in conjunction with a non-pressurized face TBM. Each tunneling project
is evaluated on a case by case basis to
mitigate and minimize any settlement and
instability concerns.
Shashi Kumar, public works director
for Missouri City, reviewed city projects,
plans and technical needs. As part of a
regional water supply initiative and in
partnership with 30-plus other Municipal
Utility Districts (MUD's) and private sector
groups, the Missouri City is expanding capacity of its surface water treatment plant
(SWTP) to meet projected growth and the
Fort Bend Subsidence District groundwater
conversion mandates.
Another project will regionalize and
expand capacity at the Missouri City Steep
Bank Flat Bank Wastewater Treatment
Plant (SBFB WWTP), from three to 4.5 million gallons per day, due to rapid growth in
master planned developments within the
Sienna and Riverstone area.

Transportation projects & issues

CIGMAT graduate students supported Director Dr. C. Vipulanandan in presenting the 25th annual
Conference & Exhibition.

MAY 2020 | UConOnline.com

The second technical session, on
"Transportation Projects and Issues" and
related challenges, was moderated by Stanley
Yin from Tolunay-Wong Engineers, Houston.
John Tyler, deputy director of the Harris
County Toll Road Authority (HCTRA)
discussed ongoing projects and plans
to improve mobility throughout the
130-centerline-mile system.
The 2020 Capital Improvement Projects
(CIP) includes approximately $1.7 billion
to continue widening parts of the Sam
Houston Tollway and adding a new crossing,
connecting Hardy Toll Road into downtown
and constructing the Lorraine underpass,
designing and constructing interchanges,
developing a 100,000-plus-square-foot
Customer Service facility to centralize operations, and relocating EZ TAG stores.
Bridgette Towns, executive vice
president of Project Management and
Engineering at Houston's METRO, talked
about maintenance and expansion projects
for the coming years, including growth of
the light rail system, especially around the
medical center, and development of new
neighborhood transportation facilities.

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Underground Construction - May 2020

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