Tuesday, September 2, 2014

Railroad Routine Bridge Inspection

The past few weeks I've been busy working long nights for bridge and tunnel inspections. Our inspections were located in Revere, South Boston and Brookline and each had its own unique access requirements.

The Revere bridge spans over the Blue Line and was inspected using ladders since it was a short span consisting of prestressed concrete butted box beams in good condition. Using ladders allowed us more time for inspection since we did not have to wait for a hi-rail lift truck to be put on and driven to the bridge. We were able to get on track around 1am and finished just before they needed power back.
The South Boston bridge spans over the Red Line and MBCR commuter rail tracks and was inspected with ladders even though it was a larger span consisting of prestressed concrete butted box beams in good condition. We decided to use ladders since we could inspect the commuter rail portion starting at 10pm and finish before the MBTA would allow us access to the Red Line around 2am. There was also a small portion over a dirt road with no traffic at 1am. Working in all three sections could not be accomplished using a hi-rail lift since the truck would require traveling further south to be able to get onto the tracks.
The Brookline bridge spans over the Green Line near the Beaconsfield Station and was inspected with a 40 foot hi-lift since the bridge was wide and consisted of 57 rolled steel beams. We were able to get on right near the bridge just after 1am and finished the wide bridge just before power was needed back.

Thursday, July 10, 2014

2014 ASCE Concrete Canoe Winner

Brings me back to the days when my team qualified with our canoe Cherry π

2014 ASCE Concrete Canoe Winner

Here are a few photos from back at school when we were placing the concrete.

Tuesday, June 17, 2014

Owensboro KY Routine and Fracture Critical Inspection

Yesterday I arrived in the balmy city of Owensboro KY to inspected the Glover H. Cary Bridge. The carries Indiana 161 and Kentucky 2262 over the Ohio River. Today we began our inspection of the truss starting at node 0. By the end of Day 1 we reached node 20 on the upper chord with two teams and node 24 on the downstream lower chord. With a high temperature of 93 degrees we were spent and my right hand had begun to cramp up. The truss makes great use of solar panels for powering the lighting, which were not on during inspection hours for safety. All of our climbers are now SPRAT certified and we are looking forward to many more climbing projects coming up at the end of the summer.

Here is a taste of the climbing that I caught with my GoPro

Here is the bridges information from Wikipedia:
The Glover H. Cary Bridge is a continuous truss bridge that spans the Ohio River between Owensboro, Kentucky and Spencer County, Indiana. It was named for the late U.S. Congressman Glover H. Cary (1885–1936), and opened to traffic in September 1940. It was originally a toll bridge, but tolls were discontinued in 1954.

The bridge was funded through a $1.03 million federal grant, part of President Franklin D. Roosevelt's New Deal program, and public fundraising efforts. At first, the bridge connected Kentucky Highway 75 to Indiana Highway 75; in 1954, Kentucky 75 was redesignated U.S. Highway 431 and Indiana 75 became U.S. Highway 231.

The bridge was closed temporarily for a day and a half the weekend of March 13, 2011, due to the need for emergency repairs to the bridge deck with traffic temporarily detoured over the William H. Natcher Bridge. Following that emergency repair, transportation officials pressed ahead with planning and design on a full-depth deck rehab that was already scheduled for bidding in April 2011.

Structural condition:
Following the collapse of the I-35W bridge in Minneapolis, Minnesota in August 2007, Kentucky officials (including Governor Ernie Fletcher) sought to reassure motorists that Kentucky's bridges are safe by conducting a special safety review of all long-span bridges at that time. The Cary Bridge was subject to a detailed biennial inspection in August 2008. Kentucky and Indiana highway officials conducted a joint walk-through inspection of the structure on September 22, 2008.

On July 5, 2011, the Kentucky Transportation Cabinet closed the bridge to all traffic for a $3 million partial rehab of the bridge deck after a large hole developed in the concrete driving surface. Hall Contracting of Louisville was the prime contractor on the 3-month project. The project, which saw 40% of the bridge's deck replaced, was completed and the bridge reopened to traffic on September 30, 2011—three days prior to the October 3 deadline imposed by KYTC on the contra

Prior to its reopening, the bridge was opened to pedestrians and bicyclists for "Bridge Day" on Sept. 30; thousands of visitors crossed the 72-year-old span between the hours of 8:00 AM and 6:00 PM, when crews began preparing to reopen the bridge to auto traffic, which occurred at 6:30 PM.

Monday, April 28, 2014

Cape Cod Bridge Inspection

A couple months ago we were down on the Cape inspecting the Dennis Yarmouth Bridge. The cast-in-place reinforced concrete slab has 33 spans which carry Route 28 over the Bass River.

This was a Special Member inspection of the deck and substructure and was very helpful since we were also currently rating the structure. The Bass River flows tidally North and South.

Spans 1, 2, 32 and 33 were accessed from manholes and inspected with ladders. The lower portion of the concrete piles were inspected by boat (and went much faster after we purchased a new motor). The underside of the deck, pile cap and upper portion of the piles were inspected with a 50 foot Snooper (Under Bridge Inspection Unit from McClain). With the help of local police and traffic control, we were able to shift traffic over while we worked in the break down lane safely. 

Friday, April 25, 2014

Night Work Problems

Last week our inspection of the I-93 tunnel were brought to a halt after the bucket truck began to stall out. We couldn't risk driving the truck out of our pattern and causing an accident if it were to stall again. We had to have the state police help us with a heavy duty tow to the DOTs lot near by. The tow truck was so large that it could not bring the bucket truck to the back where visitors can park, so we ended up having to push it into a spot.

Tuesday, April 22, 2014

Boston Cable Stay Bridge Fire

An 18-wheeler collided with a taxi on the Zakim northbound shortly after 5:30 a.m..

The crash and fire led police to shut both sides of the bridge; the northbound side remained completely shut until 9 a.m., when one lane was reopened.

Josh Wardell says based on the debris strewn across the bridge, the truck was carrying apples

The accident was close to the pier tower leg and in some photos you can see the soot on the concrete. Fortunately the fire was not close to the cables which could have meant the bridge needing to be closed for inspections and repairs.

Here is an article about a fire on a cable stay bridge in Mexico where cables were damaged and repairs were made.

Mezcala Bridge Fire Damage Event
The multispan stayed or cable bridge suffered damages to one of the stay cables with a minor damage to an adjoining cable during a fire that was created due to an accident on March 17, 2007 between two school buses and a truck at the middle span of the bridge. The truck was carrying coconuts, which was the reason for the fire. After closing the bridge for vehicular traffic temporarily, the cable was replaced; though traffic was partially restored when the cable replacement started. Analysis of the cause of the fire by the American Society of Civil Engineers and the China Communications and Transportation Association indicated that the High-density polyethylene (HDPE) sheathing, which has hydrocarbon composition, was not ideally fire resistant as it caught fire and created the additional fire load which resulted in snapping of one cable line. A moot question that was posed in the analysis was "would this bridge have survived the loss of two or three adjacent cables?" Analysis also showed that multiple cables could be included in a fire caused by a lightning strike.

Bridge designers have examined the lacunae in design of major long span bridges of various types in the world, keeping in view the failures that have occurred in many bridges including the limited failure of the cable of the Mezcala Bridge due to a single point loading event that occurred due to a fire. This study was done with the objective "to enhance the reliability and safety of these major structures in the built environment." The approach now under consideration for cable stayed bridge is "a more rational approach from assigning factors of safety to key elements such as suspenders and stay cables, to setting depth and stiffness requirements

Wednesday, April 16, 2014

Cable Stay Bridge Inspection

Last October I was part of a cable stay bridge inspection in Boston, MA. While I was away in Kentucky inspecting, the rest of my office was busy inspecting the underside and beginning the lower section of the piers and cables.

After I arrived home I had a day off and I began my part of inspecting the upper portion of the pier towers and cables which reached heights of 270 feet over the roadway. Since equipment could not efficiently inspect that high we used SPRAT climbers (myself and other guy from PA). We started by carrying over 1,000 feet of rope to the top of the north tower and rigging up our lines and rescue lines. That night we began to inspect the northern cables. With limited hours (11pm to 3am) we had little time to inspect since we were not allowed to enter the towers until lane closures were out. The first few nights were mainly learning what was the most efficient way to climb. The limiting factor for this bridge was our need for night work and thus lane closures. Luckily for us weather was good and winds were calm (less than 10 mph most nights).

As far as how we climbed, for the concrete pier towers we were able to climb out of the top at the aviation beacon and descend to the portion that was inspected by man-lifts and then ascend back up to the beacon. The first few nights we tried different ways such as ascending from a man-lift about 110 feet above the roadway (figured out that we can climb faster than a man-lift). Next we tried rope to rope transfers from the access vent located about 130 feet over the roadway. This was fast but each night we had to tie off the ropes which led to us ending almost an hour early for this.

For inspecting the cables we started off just like we did before from the aviation beacon but we carried a pair for rollers which were used to hold us ear the cables. This allowed us to stay within an arms reach of the cable we were rolling on and allowed us to see the cable below us. When we were low enough we exited the cable onto a man-lift which was waiting for us. Most nights we inspected 6 cables, we originally thought we could inspect more each night but due to less time each night we weren't able to inspect the 9 we thought we would be able to.