Big boom delivers

Three Putzmeister truck-mounted concrete pumps, including the company's new M 70-5, have been used by Associated Concrete Pumping to place concrete on the "Oakland Touchdown" section of the new San Francisco-Oakland Bay Bridge.

Sacramento's Associated Concrete Pumping is the first company in the US to purchase the BSS 70-5.16 H large-boom truck-mounted concrete pump. The BSS 70-5.16 H features a five-section boom, has a vertical reach of 70 m and a horizontal reach of 65 m.

The boom uses a Roll Z (RZ) folding mechanism and has a slewing circle of 365°.

In order to continuously concrete the bridge-approach superstructures using a wet-on-wet laying process, Associated Concrete Pumping also used a Putzmeister BSF 58-4.16 H and a BSF 63-5.16 H from its fleet alongside the truck-mounted concrete pump.

The San Francisco-Oakland Bay Bridge consists of a 3.1 km-long western bridge and a 3.2 km-long eastern bridge, connected near the bay's midpoint by the Yerba Buena Island tunnel. The eastern span of the bridge, a double-deck truss suspension bridge built in 1936, will be replaced by a new bridge. The "Oakland Touchdown", at its eastern end, is where it reaches the California mainland.

The new East Bay Bridge is being built slightly to the north of the old bridge. Instead of a double-deck cross section, it will have two parallel superstructures, one to hold each of the two 24 m-wide carriageways (carrying five lanes in each direction) with hard shoulders, and also a path for cyclists and pedestrians.

The US$ 6.2 billion project is being constructed for the California Department of Transportation (CDoT), with some of the financing set to come from toll revenues. The tender for the "Oakland Touchdown" part of the bridge was won by Californian construction company MCM Construction, with a bid of US$ 178 million. All work on the bridge is expected to be finished by 2012.