Upon opening, the Bayonne Bridge was awarded the distinction of being "the most beautiful bridge of steel erected" by the American Institute of Steel Construction. The 26,000 tons of structural steel also make the Bayonne Bridge the fourth largest steel arch bridge in the world. But in recent years, the concrete of the New Jersey abutment began showing signs of deterioration and cracking. Following several failed attempts at rehabilitation, the Port Authority turned to its number one trusted consultant for answers – they turned to Modjeski and Masters.
Our experienced team of technical experts identified Alkali-Silica Reaction (ASR) as the cause of the concrete cracking – a condition resulting from the internal expansion of a resultant gel that is produced when silica-laden aggregate is subjected to moisture. Modjeski and Masters responded by developing an innovative solution to arrest further concrete cracking in all directions: A post-tensioning design providing tri-axial compressive stress (or tri-axial confinement) greater than the internal ASR pressure. First, our plan called for a high-strength concrete encasement to be constructed around the abutment to minimize moisture penetration of the existing concrete. Next, 181-horizontal P/T tendons and 254-vertical rock anchors would need to be installed to establish the tri-axial confinement. Coring bits were utilized to drill the new concrete for the tendon installation, and rotary percussion drilling was utilized in existing concrete. To achieve the specified tight drilling tolerances, a high-tech system was employed by the contractor to continuously monitor and correct the direction of drilling. Low alkali grout was specified to minimize the possibility of replenishing the alkalinity content of the existing concrete. In the end, nearly 5.5 miles of drilling was completed, and nearly 245 miles of P/T strand was successfully installed to neutralize the cracking.
Both Modjeski and Masters and the Port Authority received several accolades following the completion of this project, including The Post Tensioning Institute’s 2008 Award of Excellence for Bridge Rehabilitation. As active partners, we worked closely with the Port Authority to create a great bridge experience – it’s what drives us to maintain the bridges that connect our clients’ communities. It’s what continues to drive every Modjeski and Masters bridge project.
Modjeski and Masters responded by developing an innovative solution to arrest further concrete cracking. In the end, nearly 5.5 miles of drilling was completed, and nearly 245 miles of P/T strand was successfully installed to neutralize the problem.
Dr. Barney T. Martin, PE (Principal-In-Charge)
Dr. Wagdy G. Wassef, PE (Project Manager)
Nicholas D. Theofanis (Project Engineer)
Martin J. Smith, PE (Project Engineer)
Tibor B. Dallos (Engineering Technician)