Pony Truss Special Member Inspection

A few weeks ago I was down in Burrillville RI inspecting a pony truss. The special member inspection consisted of the superstructure and deck since the bridge is load posted for 10 tons.

Two girders were added in 2008 to support the floorbeam and deck system with threaded hangers, the remaining pony truss is ornamental but is still inspected. In addition to the girders the state also added stop signs at each end to help reduce the impact on the structure.

The structure carries RI 98 over the Nipmuc River spanning 74.1 feet and has a width out-to-out of 24.6 feet.

We inspected the majority of the underside with a boat and just used paddles since there was little to no flow present. The west truss  diagonals, verticals and top chord were easily and safely inspected since there is a sidewalk running along the full length. The east truss was inspected by free climbing (100% tied off even though its only 5 feet over the water).

While inspecting we noticed numerous overweight trucks passing over the structure, I usually try to take a photo of the truck and write down the trucks plate number and any other information.

Not sure what to think of this

Not sure if this is actually from the NCDOT
Weird NCDOT Video

Continuous Warren through truss bridge

A few weeks ago I traveled to Kentucky for an inspection of a Continuous Warren through truss bridge. The truss was built in 1985 (same age as me!). The bridge is in good condition which is surprising since I am use to the corrosion in New England.

The bridge has a total length of 2,314.4 feet with the main span over the Ohio River spanning 740.0 feet. The deck has a width of 44 feet and carries 13th Street one way traffic northbound with three lanes.

It was my first experience with tv news crews being interested in an inspection, sure enough we made it onto the new that evening with video of our lane closure before we asked them to kindly leave our traffic pattern.

Using limited equipment the majority of the inspection was done using rope access or free climbing. The vertical members were inspected by rope with drops up to 84 feet. The top chord was inspected using a simple flip line and always remaining 100% tied off. The chord consists of built up welded members and gusset plates.

ASCE 2013 Report Card for America's Infrastructure

In 2013 America's infrastructure received a D+ which has been upgraded from four years ago when the infrastructure received a D.

Here is a quick break down:

Water and Environment

• Drinking Water: The grade for drinking water improved slightly to a D.
• Hazardous Waste: The grade for hazardous waste remained unchanged at a D.
• Levees: Levees again earned a near failing grade of D- in 2013. 
• Solid Waste: The grade for solid waste improved in 2013, and it earned the highest grade of B-.
• Wastewater: The grade for wastewater improved slightly to a D.

Transportation

• Aviation: Aviation again earned a D.
• Bridges: With the overall number of structurally deficient bridges continuing to trend downward, the grade improved to C+.
• Inland Waterways: Inland waterways received a D- grade once again as conditions remain poor and investment levels remain stagnant.
• Ports: This new category for 2013 debuted with a grade of C. 
• Rail: With high ridership and greater investment in the system, the grade for rail saw the largest improvement, moving up to a C+ in 2013.
• Roads: Targeted efforts to improve conditions and significant reductions in highway fatalities resulted in a slight improvement in the roads grade to a D this year.
• Transit: The grade for transit remained at a D as transit agencies struggled to balance increasing ridership with declining funding.

Public Facilities

• Public Parks and Recreation: The grade for parks remained unchanged at a C-.
• Schools: Schools received a D again this year.

Energy

• Energy: The grade for energy remained a D+.

For the full report see the ASCE Report Card site which breaks down into each state and category.

Here is there note about my states bridge (Massachusetts)

MassDOT is responsible for the inspection and rating of over 5,000 bridges throughout the Commonwealth of Massachusetts. Approximately 10% of these structures are classified as Structurally Deficient and require either major rehabilitation or replacement. Since the establishment of the $3 billion Accelerated Bridge Program in 2008, MassDOT has focused on replacing or repairing over 200 bridges and has already succeeded in reducing the number of Structurally Deficient bridges at a time when most states have been experiencing increases. MassDOT has accomplished this by implementing progressive construction techniques including utilizing prefabricated bridge elements (such as the Fast-Fourteen Bridge Project on I-93 in Medford) and utilizing self-propelled modular transporters (such as the Route 2/2A project in Phillipston). These innovative techniques reduced the construction duration and thereby limited the inconvenience to drivers. In order to maintain the progress made by the Accelerated Bridge Program, continued funding for the program—which is expected to expire in 2016—is needed. Without this funding, the number of Structurally Deficient bridges will again escalate, impacting safety, resulting in more expensive remedial repairs, and impacting vital transportation links that serve the Commonwealth.

Cantilevered Warren through Truss Bridge (riveted)

A few weeks ago I traveled to Kentucky for an inspection of a riveted Cantilevered Warren through truss bridge. The truss was built in 1930 and rehabilitated in 1986. The bridge is in good condition and I was surprised since I am use to the corrosion in New England.

The bridge has a total length of 2,277.3 feet with the main span over the Ohio River spanning 738.7 feet. The deck has a width of 22 feet and carries 12th Street one way traffic southbound.

It was my first experience with news crews being interested in an inspection, sure enough we made it onto the new that evening with video of our lane closure before we asked them to kindly leave our traffic pattern.

Using limited equipment the majority of the inspection was done using rope access or free climbing. The vertical members were inspected by rope with drops up to 115 feet. The top chord was inspected using a simple flip line and always remaining 100% tied off. The chord consists of built up riveted members and eye bars with pinned connections.

Besides areas of minor corrosion and minor impact damage the most sever deficiencies were areas of pack rust between gusset plates and pins.

Continuous Prestressed Post-tensioned Segmental Concrete Box Girders

Last week we inspected four ramps in Boston and Cambridge Mass near Leverett Circle and the Boston Sand and Gravel.

The ramps take traffic from the Tobin Bridge to I-93, Zakim BridgeLeonard P. Zakim Bunker Hill Memorial Bridge, Leverett Circle or Storrow Drive. The ramps consist of continuous prestressed post-tensioned segmental concrete box girders.

To inspect the exterior of the box girders an 80' man lift was used since most of the structures were no accessible with smaller lifts due to on going construction and a park. The exterior inspection consisted of visually inspecting the box girders, piers and measuring the bearings for movement.

The interior of the box girders were inspected with three man teams since they are considered a confined space. When inside the box girder the inspection team needs an air meter, rescue air tank and radio, luckily we have only had to carry these once down the interior since there is a hatch at both ends. The interior inspection consisted of visually inspecting (even though we were always within an arms reach)the box girders even though we were always within an arms reach, utilities and measuring the pintle slots for movement. 

Tunnel Overhead Inspection

The other week I was out in East Boston to inspect the Callahan Tunnel exhaust plenum as part of the Overhead inspection.

The Callahan Tunnel was constructed in 1960, 60 feet below Boston Harbor. The tunnel has an inside diameter of 28 ' and carries two travel lanes with an ADT of 20,000. We inspected the exhaust plenum from station 8+77.8 to 57+72.1 which comes out to be almost a mile each way hunched over.

The exhaust plenum carries exhaust from the tunnel out at the vent buildings located at each end of the tunnel. The ceiling panels are held up by hangers and supplementary hangers labeled L2, L1, M, R1, R2. The hangers which have gaps require a supplementary hanger that cannot be loose. Many of the hangers have  supplementary and very few had gaps without a  supplementary . The concrete liner had numerous hollow areas and a few areas of cracking with efflorescence.  

Moving around in the plenum is difficult and depending where in the tunnel the air can be come very still and hot. By the end of each day your clothes, mask and exposed skin are covered in soot. This is pretty common when inspecting an exhaust plenum though.

Natural Bridge in Virginia

Last week on vacation I took a road trip down to Kentucky and Tennessee. On the way back I stopped at the Natural Bridge in Virginia.

The natural arch spans 90 feet across Cedar Creek and is up to 215 feet over the creek floor and consists of a limestone strata. The bridge carries US highway 11 and when cross the bridge has fencing so you can't see the view from the top (believe me I tried).

When I was at the natural bridge my first thoughts were on how they inspect a land bridge and what type on monitoring they is performed on it. I thought it would be a simple google search but so far I haven't found any information on it.