Fracture Critical Bridge Inspections

So after a couple buys months of design work, I'm back on inspections.

While I was in the office, a few others were out in the field complete fracture critical inspection which were held up with paper work discrepancies between RIDOT and AMTRAK.

Right now I'm trying to do my best to help complete a few of the reports. The reports end up being slightly easier than a routine or inventory inspection since they focus on only the fracture critical elements of the bridge.

A fracture-critical bridge is one that does not contain redundant supporting elements. This means that if those key supports fail, the bridge would be in danger of collapse. This does not mean the bridge is inherently unsafe, only that there is a lack of redundancy in its design. -From AASHTO

Fracture critical members a usually defined by having an AASHTO fatigue detail or category which is greater than C (A being low and E being high risk).

Typically bridges such as steel trusses, thru girders and steel pier bents contain fatigue details which are greater than a C.

Bridge  1

  Bridge 2  

 Bridge 3  

 Bridge 4  

Bridge 5 

Bridge 6 

  

Bridge 7 

 

Bridge 8  

Crusell Bridge inaugurated in Helsinki

The Crusell Bridge, was inaugurated today in Helsink and is now one of the more prominent bridges in Finland was designed by WSP Finland. It was built using Building Information Modelling (BIM).

The bridge was commissioned by Helsinki and constructed by Skanska and features two travel lines and in the future a tram line.

City of Helsinki organized an international design competition for the bridge project in 2001. WSP Finland’s winning proposal was “Sea Swords”, a dual-spanned, asymmetrical cable-stayed bridge with beams measuring 302 ft and 167 ft with a horizontal clearance of 82 ft. WSP Finland’s Business Area Director Pekka Pulkkinen was in charge of the technical design of the bridge.

”The building information modelling enabled the contractor to see the construction phases in advance and define for example reinforcements much better than by using an ordinary level drawing. Also, they could order all materials just-on-time,” says WSP Finland’s Oulu Bridge Unit’s manager Antti Karjalainen.

“The model allows simulating all later changes to the structures. Maintenance projects during the life-cycle of the bridge will also benefit from the model”, Karjalainen concludes.

Crusell Bridge won an award for accuracy in reinforced concrete structures. The bridge was also been listed as one of the most notable building solutions in the 2nd edition of BIM Handbook (R.Sacks & Co).

Rolled Steel Beam Bridges

So at near the end of May (ya I've been pretty busy and lacking on the updates) I inspected two six rolled steel beam bridges and bottom flange cover plates.

The bridges carry Route 24 North and South in Tiverton. This was my first time in Tiverton and I have to say that it is a very picturesque spot locate right on the coast, if you have a chance check it out. 

The rolled steel beams had minor deficiencies with section loss to the bearing stiffeners. The were in pretty rough shape at the expansion end with heavy spalling to the backwall which extended throught to the wearing surface.

Nearing the end of the inspection the bucket truck started to have problems operating and needed to be reved (sp?) to allow the enough hydraulic pressure to move smoothly (or move at all)

Wicked Busy with Bridges

Title really says it all, I've been really busy helping with five bridge designs which we are trying to complete by the end of the month. So far I've "only" been working around 60 hours but as the date approaches I think that number will get higher.

Two bridges consist of 7 horizontally curved steel plate girders. One bridge will consist of 7 steel plate girders (straight). The final two will consist of conspan rigid frame sections.

The existing abutments be cut down and remain for channel protection. The proposed footings, abutments and wingwalls with all be precast pieces which will be assemble off site before hand to make sure they are fit correctly.

Also found out that I will be part of an inspection team which will be inventory inspections for several non-NBIS bridges in RI, hopefully some near the beach this coming summer.

Timber Pier Bents Special Member Inspections

Still very busy with design work and trying to update when I have a chance.

Back on April 14th I inspected two special member bridges. The first bridge has a timber deck with two timber pier bents and spans over Woonasquatuck River in North Providence. 

The Special member inspection only focused on the timber pier bents which had checks and splits with section loss to the columns along the water line.

The second bridge has rolled steel beams which are two span continuous and spans over Bucks Horn Brook in Coventry.