Soil Nail Wall 7 Excavation

Teichert Construction began excavation operations last week for Soil Nail Wall 7, located at the northern project limit. The existing hillside excavation consists of removing occasional sandstone and cemented rock formations. In addition to excavators and blade equipment, Teichert Construction is using breakers to chip and remove the bedrock material. After each "lift" is excavated, soil nails are installed to secure the hillside followed by the shotcrete wall facing.

Teichert Construction excavates the hillside for the initial wall lift.

Exposed rock within the soil strata along the hillside cut face.

Teichert Construction uses a breaker to remove sandstone along the cut face.

Installed soil nails along Soil Nail Wall 7.

Soldier Pile Wall Work Continues

Teichert Construction has completed a signifcant portion of the soldier pile retaining walls required for the road widening at the southern project limit. Steel piles were installed and cast in concrete holes along the hillside. Teichert Construction crews then excavated the hillside and installed timber lagging to retain the hillside slope. A concrete facing wall be installed in front of the timber wall with an architectural finish in the following months.

Teichert Construction removes "lean" concrete and soil around the piles to install timber lagging.

Southbound view of the Soil Nail Wall 2.

Bridge Work Continues

In the last month, Teichert Construction has made significant process in completing the construction of the Brushy Creek bridge widening. Wood form work for the bridge structure was erected and steel reinforcing bars installed. The "stems and soffit" of the bridge structure was poured with only the main deck pour remaining.

Teichert Construction erects forms for the "stems" that come up from the bottom of the bridge (soffit).

Reinforcing steel bars and installed for the stem and soffit.

Northbound view of the bridge widening.

Completion of concrete "stem & soffit" pour.

Soil Nail Wall 4 Production Nail Installation Begins

After completion of verification nail testing and waiting for the proper soil nail materials to be delivered, Teichert Construction began installation of production nails at the Soil Nail Wall 4. The results of verification nail testing confirmed the appropriate soil nail lengths as well as allowed for a redesign of the nail layout for ease of construction. Six inch diameter holes are drilled into the hillside to design lengths prior to installation of the actual steel nail. Grouting of the nail must take place immediately after drilling to prevent cave-ins. Wire mesh and steel reinforcement are then installed along the soil cut face prior to the installation of the shotcrete wall facing.

Installed soil nails along with the Soil Nail Wall 4 cut face extend outward. The black geocomposite drain strips are installed against the soil and will be extended down as each soil nail lift is excavated.

Reinforcing steel bars extend above the cut face to eventually support the extension of a concrete cantilever wall.

Shotcrete installation operation at Soil Nail Wall 4.

A soil nail extends through the reinforcing steel, wire mesh, and initial layer of shotcrete.

Soldier Pile Wall 2 Work Begins

Teichert Construction began construction of Soldier Pile Wall 2 at the southern project limit. Besides the use of soil nails to secure the hillside along Vasco Rd, soldier pile wall retaining systems will be used to stabilize the minor hillside cuts. Approximately 20 to 30 ft deep holes are drilled to accommodate concrete cast in place steel piles. Timber lagging will be installed in between the steel piles prior to the final concrete facing wall. Upon completion Soldier Pile Wall 2 will be approximately 12 ft tall at the highest location.

Drilling rig staged at Soldier Pile Wall 2 location.

Drilling down to pile tip elevation.

Steel pile secured in the proper location prior to concrete pour.

Brushy Creek Bridge Abutments Complete

Teichert Construction completed the Brushy Creek Bridge abutments by pouring them in early August. The abutments secure the bridge structure itself to the footing foundation. Steel reinforcement extends from the footing up into the abutment, which will eventually connect to the bridge deck.

View of Abutment 1.

Falsework installation at Abutment 2.

Laying out falsework girders at Abutment 1.

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.

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.

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.