GERALD DESMOND BRIDGE
The Gerald Desmond Bridge Replacement Project was an approximately $1billion design‐build project to ensure the safety of commuters and truck drivers as well as protect southern California’s important role as a major trading hub.
In order to construct the new bridge, the Port of Long Beach required groundwater monitoring during construction dewatering activities. This ensured that dewatering was not significantly drawing down the groundwater level around the site. Group Delta installed and monitored 12 multi-nested piezometers around the project site to monitor groundwater levels in the unconfined and confined aquifers.
SAN GABRIEL TRENCH
This project entailed the lowering of 1.4-miles of Union Pacific rail line in a trench through the City of San Gabriel to provide vehicles and pedestrians safe crossing over the tracks.
Instrumentation highlights included:
Installed and monitored crack gauges and tiltmeters to assess the impact of construction on nearby buildings.
Installed inclinometers in piles to measure the effectiveness of pile construction.
Tiltmeters and in-place inclinometers are monitored with systems of remotely monitored data loggers.
Data is posted on the web-based data management system for clients to easily access at any time.
Providing geotechnical instrumentation that includes traversing probe inclinometers, in-place inclinometers, tiltmeters, and crack gauges.
TRAMPAS CANYON DAM
The purpose of this dam reconfiguration project was to raise this earth-fill embankment dam and update appurtenant facilities (i.e., an inlet/outlet structure, inlet/outlet tunnel and pipeline, spillway, roadways, and a pump station), among other construction features. The Geotechnical instrumentation was in support of the reconfiguration of Trampas Canyon Dam.
Monitoring equipment installed at the dam included the following instruments:
Six inclinometers ranging from 30 feet (ft) to 170 ft below ground surface (bgs);
Twelve automated monitoring wells with vibrating wire piezometers;
Four weir monitoring systems.
Automated Data Acquisition System to collect data from the piezometers and weirs and transmit it to a web-based data management system.
Thirty-four surface settlement points.
This nine-mile extension of the existing Metro Purple Line Wilshire/Western Station to the West Los Angeles/Veterans Affairs (VA) Hospital site will enable commuters to travel entirely below ground between downtown LA and Westwood in just 25 minutes.
Instrumentation highlights included:
Providing instrumentation and monitoring for a 3.9-mile tunnel section, including 3 stations.
The extensive instrumentation systems included 32 vibrating wire piezometers, 27 ShapeAccelarray (SAA) inclinometers, 46 in-place inclinometers (IPIs), 161 multi-point borehole extensometers with vibrating wire piezometers, 910 strain gauges, 16 load cells, 500 crack gauges, and nine total stations that scan 220 building settlement markers, 483 ground surface settlement reference markers, and 16 utility monitoring points.
All instruments with the exception of the crack gauges are automated and remotely upload data to a cloud-based data management system Automated Data Accusation System (ADAS).
Data from each instrument was uploaded to the DMS, processed, and graphed.
The Lakeside library is an approximately 17,000 square-foot single-story library that will serve the community of Lakeside and surrounding areas. During the initial subsurface investigation conducted on the propriety, a relatively continuous, very weak, compressible, and potentially sensitive 8- to 12-foot-thick layer of soil was encountered at a depth of 18 to 30 feet below ground surface along the western side of the site. To consolidate the soil within this zone, a surcharge soil stockpile was placed over the area using on-site materials. Settlement sensors were placed at the bottom of the stockpile to monitor the rate of settlement and determine when conditions stabilized. Once no further settlement was detected, the surcharge stockpile was removed.