ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

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An innovative bridge design using high-performance precast, prestressed concrete allowed construction to proceed without entering a 170-ft-wide environmentally sensitive area (ESA) at the bottom of a creek, thus meeting resource agency permit requirements. In addition, access to the bottom of the creek was limited to a 90-ft-wide construction easement. This design was developed using a collaborative approach among the design team, t h e o w n e r, t h e p re c a s t c o n c re t e producer, the contractor, and the city. This collaborative approach continued through the construction phase to deliver this challenging project with great success. Background Construction of a new community, appropriately named The Preserve, is underway in the coastal city of Carlsbad, Calif. Bisecting this community is Buena Vista Creek, which is now spanned by the newly constructed El Salto Falls Street Bridge. This bridge carries two traffic lanes, two bicycle lanes, and two sidewalks, as well as two 12-in.- diameter potable water lines, a 6-in.- diameter recycled water line, and a 12-in.-diameter gravity sewer line below the deck. The sewer line had to be operational before property sales within the community could begin, which placed it and the supporting bridge on the critical path of the project. Upon completion of all improvements within the community, the city of Carlsbad will take over ownership and maintenance responsibilities of the infrastructure from Cornerstone Communities, the developer. Buena Vista Creek and the adjacent open space is an environmentally sensitive riparian habitat; just outside of the community is El Salto Falls, a formally designated Native American Sacred Site. To avoid a lengthy permit process with the U.S. Army Corps of Engineers, the owner required the bridge to be constructed without e n t e r i n g t h e 1 7 0 - f t - w i d e E S A a t the bottom of Buena Vista Creek. F u r t h e r m o re , t h e c o n t r a c t o r w a s required to stay within the 90-ft-wide easement when accessing the creek from the top of the banks. Design The design team considered several options that allowed construction without profile EL SALTO FALLS STREET BRIDGE / CARLSBAD, CALIFORNIA BRIDGE DESIGN AND CONSTRUCTION ENGINEER: T.Y. Lin International, San Diego, Calif. PRECAST SPECIALTY ENGINEER AND PRECASTER: Oldcastle Precast, Perris, Calif.—a PCI-certified producer ENVIRONMENTAL DOCUMENTATION: HDR Inc., San Diego, Calif. CONTRACTORS SPECIALTY ENGINEER: D.H. Charles Engineering Inc., Cardiff, Calif. PRIME CONTRACTOR: LB Civil Construction, Escondido, Calif. POST-TENSIONING CONTRACTOR: Dywidag Systems International (DSI), Long Beach, Calif. GIRDER ERECTION: Maxim Crane Works, San Diego, Calif. by Dr. Jay Holombo and Wade Durant, T.Y. Lin International, and Jon Grafton, Oldcastle Precast EL SALTO FALLS STREET BRIDGE HIGH-PERFORMANCE PRECAST CONCRETE IS KEY TO COST-EFFECTIVE ENVIRONMENTAL IMPACT AVOIDANCE Aerial photo shows the newly constructed El Salto Falls Street Bridge in relation to the environmentally sensitive area (ESA) within Buena Vista Creek, as denoted by the orange fence. Under the bridge, the ESA is 170 ft wide at the bottom of the creek. All Photos and Illustrations: T.Y. Lin International. 16 | ASPIRE Summer 2017 P R O J E C T

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