I-495 bridge replacement over Merrimack river in Haverhill, MA

Siefert Associates, LLC continues to provide construction engineering services for SPS New England in support of the I-495 bridge replacement over Merrimack river in Haverhill, MA. The Scope includes the design of a temporary work trestle and ramp as well as temporary support towers for the erection of the new girders. This presents some challenges such as accounting for the integrity of said structures during extreme natural events like high wind storms or flooding, as well as the stability while under high lateral loads due to large machinery. The picture below shows the bridge in its existing condition.