The Vasco Rd Safety Improvements Project - Phase 1 is designed to improve the safety of approximately 1 mile of Vasco Rd between the cities of Brentwood and Livermore. This stretch of twisting Vasco Rd has heavy, fast moving traffic and a history of serious injury accidents. The project consists of installing a concrete median barrier along the 1 mile project limits and widening the southbound pavement to provide a truck climbing lane, thereby eliminating the gap in the existing truck climbing lanes along Vasco Rd. To accommodate these safety improvements, 6 retaining walls, storm drains, wildlife crossings, and a bridge widening will be constructed. This project is anticipated to take 1.5 yrs (2 construction seasons) to complete, anticipated in December 2011. Check out this blog from time to time to see updates on construction progress and facts about the project.

Saturday, July 17, 2010

Brushy Creek Bridge Abutment Work Begins

Earlier this past week, Teichert Construction completed the Brushy Creek Bridge concrete footing pour. Upon completion of this operation, construction workers stripped the wooden forms to expose the concrete footing and began erecting the abutment forms. As this operation proceeds, one can visualize the bridge structure itself as the foundation begins to come up. Reinforcing steel (vertical bars) were installed in the footing to extend up into the abutments to secure the bridge to the footing foundation.


Stripping the footing forms at Abutment 2.


View of Abutment 2 footing (foreground) with Abutment 1 forms in the distance.


Abutment 1 forms being erected.

Brushy Creek Bridge Footing Pour

This past week Teichert Construction completed their first major concrete operation, Brushy Creek Bridge footing pour. A concrete pumping truck set up between the two bridge abutment footings while concrete trucks lined up to supply the materials. County Inspection staff monitored the pour itself while County Materials Testing laboratory staff verified the material quality and obtained samples for further quality assurance sampling.



Concrete being pumped into the Abutment 1 footing form.


Concrete at the Abutment 1 footing, lowest step.


County Materials Testing Laboratory Staff obtaining concrete samples onsite for quality assurance compressive strength testing.

Saturday, July 10, 2010

Bridge Footings and Shotcrete Test Panels

This past week Teichert Construction began forming the bridge footings and installing the rebar in anticipation for a concrete pour next week. The recently driven piles are anchored to the footing via rebar which also extend up into the bridge abutments. Pre production soil nail wall work continued this pass week with additional verification nail testing and pre construction shotcrete test panels. Upon installation of production soil nails, shotcrete will be used to in conjunction with wire mesh and reinforcing steel to form the retaining wall face itself. This will maintain the wall face integrity while the soil nails stabilize the hillside behind the retaining wall. Test panels of shotcrete are built by Teichert Construction prior to actual wall construction for Construction Inspection to verify the quality of shotcrete workmanship and confirm its strength properties prior to production.


Concrete forms and rebar at the Abutment 1 stepped footing.


Concrete forms and rebar at the Abutment 2 footing.


Construction of a shotcrete test panel (with reinforcing steel).


Pre production shotcrete at a verification nail face.

Monday, July 5, 2010

Pile Driving and Verification Nails

This past week Teichert Construction completed pile driving installation for the abutment foundation at Brushy Creek. Forty-five to 60 ft long steel H-beams were driven into the soil beneath the abutment footing to provide a secure and stable foundation for the bridge widening. The piles are struck by a pile hammer with sufficient energy to drive the steel through the surrounding creek alluvium and deep into bedrock. Observation of the pile driving operations by County Inspection confirmed the existence of a hard sandstone layer (at shallow depths at the northern abutment) within the foundation's geological layer. This rock stratification provides a good substrate for the piles to secure the bridge footing and abutment. Other construction operations last week included the completion of exploratory drilling for the soil nail retaining walls at the northern and southern project limits. Verification nails were installed to confirm County Design's soil assumptions for the retaining walls. Soil nail retaining wall systems will be constructed as part of the Vasco Rd Safety Improvements project. "Soil nails" of various lengths are installed in bored holes along the hillside. The nails are then grouted in place with high strength concrete. As a complete system, the friction created between the grouted nails and existing soils secure the hillside and prevent slides from occurring. The current verification nail process consists of installing test nails at various locations to identify current soil conditions and quantifying the load the designed soil nails can sustain. Upon completion of this verification process, the "production" nails can be re-designed (shortened) to reduce costs if the existing soil conditions are better than originally anticipated.



Teichert Construction pile driving rig setting up at the southern abutment.



Pile driving at the southern abutment.



Piles driven (at the northern abutment) into the existing sandstone layer, which encountered competent bedrock at shallower depths than expected.



Teichert Construction drill rig beginning to bore for a verification soil nail.