South Bay Expressway, San Diego County, CA, USA

The construction of the new South Bay Expressway, connecting SR-54 and SR-905 in San Diego County, California, USA was started in 2002 and will be completed in mid-2007. The new 12.5 mile road stretches from SR-54, near the Sweetwater Reservoir, to SR-905 in Otay Mesa, near the US / Mexico international border. The highway will link the neighbourhoods of east Chula Vista with job centres in the north and the growing industrial corridor along the border.

It has been estimated that nearly 200,000 vehicles per day will travel this section of the new South Bay Expressway. This will greatly reduce traffic congestion on local streets in Chula Vista and Bonita, as well as on the parallel I-5 and I-805.

ACCESS

The project will also provide an additional access to the Otay Mesa Port of Entry as the existing road along Otay Mesa Road is becoming extremely busy. In addition to relieving this local bottleneck, the new north-south highway will also provide much needed access to developing communities in eastern Chula Vista.

Together with the connecting sections of the new South Bay Expressway to I-8 and SR-52, the new South Bay Expressway will provide a new north-south traffic corridor linking the border area and new neighbourhoods in eastern Chula Vista to the greater San Diego region and beyond.

The north-south freeways I-5 and I-805, which parallel the new South Bay Expressway to the west, are already experiencing traffic congestion. Increasing international trade and commerce are expected to bring new development in the Otay Mesa/Mesa de Otay areas – making the San Diego/Tijuana region attractive locally, nationally, and internationally.

SPONSORS AND PARTNERS

The new South Bay Expressway was designed and constructed through an innovative public-private financial partnership between the State of California and California Transportation Ventures Incorporated (CTV), a private consortium selected by Caltrans in 1990. The southern portion of the project, estimated to cost $635m, was financed by CTV through a combination of funding sources and is operated as an express toll road from SR-54 near Sweetwater Reservoir to SR-905 (Otay Mesa Road).

Once open to traffic, CTV will operate and maintain the toll road portion of the project. After the required 35 year concession, CTV will return the toll road back to Caltrans.

The financing structure of South Bay Expressway is unique and includes bank loans, a $140m federal loan facility provided by the US Department of Transportation under the TIFIA programme (Transportation Infrastructure Finance and Innovation Act of 1998) and private equity capital. Additionally, area developers have dedicated right of way valued at $48m to the South Bay Expressway project.

In addition, the northern end of the South Bay Expressway project, estimated to cost an additional $138m, was funded through local financial support committed by San Diego Association of Governments (SANDAG). The SANDAG funding is dedicated to construction of the Gap and Connector sections of the project, important un-tolled links that will connect the tolled section of South Bay Expressway to the existing San Diego freeway network.

STAGES AND TOLLS

South Bay Expressway is a two-stage project that consists of 12.5 miles of new highway connecting SR-54 near the Sweetwater Reservoir to SR-905 in Otay Mesa near the international border. The project is divided into three segments. The first two segments are the 'Gap', (a 3.2 mile publicly funded section of highway running from SR-54 to San Miguel Road in Bonita), and the 'Connector',(an interchange involving the reconstruction and expansion of an existing section of SR-54 where it intersects with the new South Bay Expressway).

The remaining 10 miles of express tollway, running to SR-905 near the Otay Mesa border, will be a state-of-the-art toll road developed by CTV. The tollway will utilise electronic toll collection technologies, which allow vehicles equipped with FasTrak electronic transponders to drive through toll plazas at normal highway speeds.

South Bay Expressway opened as a four-lane highway with interchanges at SR-54, the future San Miguel Ranch Road, East H Street, Otay Lakes/Telegraph Canyon Road, Olympic Parkway, future Birch Road and Otay Mesa Road/SR-905. The project is designed with a future scope for construction of a six to eight-lane highway plus possible future carpool lanes and transit facilities in the median.

CONSTRUCTION

The project is being constructed in two phases. Phase I is the construction of an initial six-lane freeway from SR-54 to Jamacha Boulevard, the 'Gap'. Phase II sees the construction of 9.3 miles of four-lane highway from south of SR-54 near the Sweetwater Reservoir to SR-905 near the international border. This section will be operated as a toll road.

Construction on the Gap and Connector began in the summer of 2002 and will be complete in summer 2007. The toll road portion of the project began construction in September 2003 and is projected for completion in summer 2007.

OTAY RIVER BRIDGE

One of the most remarkable feats of engineering in the whole project is the Otay River Bridge stretching across the Otay River Valley. On 28 March 2007 the last segment of South Bay Expressway’s Otay River Bridge was erected – a significant milestone in the construction of the 10-mile South Bay Expressway opening in summer 2007. The Otay River Bridge a ‘precast segmental bridge’, and there is only one other like it in California: the San Francisco-Oakland East Bay Skyway Bridge, currently under construction.

At its peak, the four-lane Otay River Bridge is nearly 19 storeys tall and will connect communities and businesses across the South Bay to Otay Mesa and the International Border. The Otay River Bridge is nearly ¾ of a mile long and 75ft wide, enough to carry four lanes of traffic. Typical spans between columns are 300ft long. The bridge is made of post-tensioned concrete, where the concrete is squeezed by high-strength steel strands to prevent cracks.

PRECAST SEGMENTAL

The construction technique is called ‘Precast Segmental’, where the precast segments are cast off site and delivered to the bridge to be assembled. The precast segmental technique allows the deck to be built ‘top-down’, and minimises the environmental impact of the project. This will be the first precast segmental bridge to open to traffic in California, and is designed to withstand large earthquake forces. There are a total of 640 segments that make up the bridge. Each segment weighs between 60 and 70 tons.

The segments are cast in a facility in Perris, California, approximately 90 miles north of the project site and are lifted into place by a steel erection gantry, which was manufactured in Italy and shipped to the site. The segments are erected using a ‘balanced cantilever method’ which minimises the construction loads applied to the columns.

There is a total of 470 miles of post-tensioning strand, enough to reach from San Diego to San Francisco. Each strand is strong enough to support 30 tons, the weight of a fully loaded concrete mixer truck. The tallest column is 190ft (19 storeys) from foundation to deck. Each pair of columns rests on a rectangular pile cap, which is 75ft wide, 50ft long and 10ft thick, and took more than 100 concrete trucks to pour.

BENEFITS

SR 125 South will provide much needed road infrastructure to the region to propel development of the localities along the route. It will reduce traffic congestion on interstates I-5 and I-805 and will also reduce traffic congestion on Otay Mesa Road and local streets in Chula Vista and Bonita.

The project will reduce drive-time from Eastlake to downtown San Diego by 34% and to Otay Mesa by 75%, improving regional mobility in the South Bay and access for residents and businesses to the employment centres on both sides of the US / Mexico border.

The South Bay Expressway will offer customers complimentary roadside assistance, including help when you run out of gas, need fluids, break down or get a flat tyre. Commuters in eastern Chula Vista will avoid 14 traffic signals that currently stand between them and the 805 Freeway.