Wrentham Rating Inspection

Down in Wrentham MA confirming measurements for a rating. Taunton Street over I-495 northbound.

Tough Commute

From Boston.com

This morning it took me two hours to reach my office by far one of my worst commutes to work. With bad weather, bad drivers and bad tires I was extremely happy when I was inside and safe.

Oldies but goodies

In my office on MLK day and will be posting some past bridges that I missed. Since it's MLK day take some time out of your day and check out the Martin Luther King Bridge which is a cantilever steel through truss in Saint Louis, Missouri.

Powder Point Bridge

I meant to post this before but it slipped my mind. Back in August my company inspected the Powder Point Bridge which gives a short cut to the Duxbury Beach. 

The bridge spans over Duxbury Bay and consists of 110 simply supported timber beam spans supported by two abutment pile bents and 109 pile bents. The bridge was built in 1987 and was designed by Universal Engineering Corp. for the town of Duxbury.

The bridge use to own the record for the Worlds oldest longest wooden bridge before being rebuilt and now it is currently 2200 feet long from abutment to abutment.

If you are from the South Shore of Mass you know if bridge very well. Ever since I was little I have crossed this bridge to get to the beach. If you are lucky enough to have a Duxbury Beach sticker you can drive right onto the beach, if not you are forced to make the walk from an expensive parking lot or a tiny free lot that never seems to be empty.



Culvert Rating

For the most part of today I have been busy trying to set up a check for a rating I worked on over the summer for a two concrete box cell culvert in Fitchburg MA. 

For analysis of the bridge I used BRASS Culvert which is a great tool to assist with the rating. Instead of using STAAD to create influence lines, locating axle locations for maximum stresses, creating interaction diagrams and calculating axial and bending capacities, BRASS Culvert allows engineers to input the culverts properties and receive an easy and quick analysis.

Anyone can make a mistake and even after double and triple checking inputs errors can still occur, so it is always a good idea to have someone check your analysis by using a different method. 

It's always fun to find random debris that makes you scratch your head

Not to sure how other consultants calculate the fill over arches and culverts but with my small amount of surveying experience I suggested we use an automatic level for quick accurate fill depths.

Being the youngest engineer in my office has its perks sometimes but usually it means doing the work others do not want to do, e.i. digging holes for pavement depths.

Thru Truss Demo

The thru truss I was inspecting today in Richmond RI is apparently being demolished soon, no more floorbeams and no deck makes for a quicker inspection.

EDIT: So today I found via Facebook that one of my friends noticed that this equipment looks like his companies and apparently they part of the force that will be demolishing the bridge

AMTRAK inspections before the snow

Down in RI inspecting the tops of AMTRAK bridges. Just finished three thru girders near Cranston. Stopped at Wein O Rama for some lunch and now down to Richmond for an other thru girder and then to Westerly for a thru truss.

Preparing for winter weather

Tomorrow I will be heading down to Pawtucket RI to inspect the tops of two AMTRAK bridges. Both bridges are fracture critical inspections with built up steel girders. Today I will be checking my equipment and making sure I have plenty of extra warm clothes, since the new is reporting a large storm to hit the Mass/RI area with up to 12" of snow  for the second time in less than a month.

Founding Dubai's skyline

While on my local intranet I noticed a new post about an article discussing the construction of Dubai's high rises from excavation to erection. The article refers to the help of a WSP Middle East structural engineer who explains the process in five easy phases. Each phase seems to incorporate parts which do not quite fit but for the average person that does not have a background in engineering or construction, this is a great article to help them understand the process.

LRFR Guidelines Revision #1 Clarifications

After a few questions from multiple consultants, RIDOT sent back responses to answer our questions.

These are our responses to your questions for clarification: (AECOM)


1. Page 21 – Load Rating Report: there is a statement in bold at the bottom regarding the color of the cover that states “… is any rating is…” My interpretation of this statement is that it is inclusive of the BP and OP vehicles. This would be a change from what we’ve been told previously (i.e. color of the cover determined only by the “legal” load vehicles)

Response: The color of the cover is not determined only by the legal load vehicles but by any rating and is independent of the controlling limit state and is strictly based on the controlling rating factors regardless of what controls the posting.

2. Page 22 – Load Rating Report Layout Table: Item 4 says “PE Stamp to be included” however there is no space on the reference sheet 24 for the stamp. Is the stamp required or just the PE number?

Response: The PE number is sufficient.

3. Page 22 – Load Rating Report Layout Table: Item 14 says “…and the written agreement of the independent reviewer.” Where can this written agreement be found?

Response: The independent reviewer should agree that the computations (Index, sketches, hand calculations..) are satisfactory in writing. Note, his signatures or initials on the computation sheets are considered a written agreement.

4. Page 24 – Summary of Bridge Rating: The new table now has a RL (TONS) input required for the HL-93 at Inv and Oper level where previously these were N/A and only rating factors were supplied. There has been some debate over what the correct vehicle weight is for the HL-93 notional load. What is the weight we should be using for this vehicle to get the rating loads (tons)?

Response: The rating of HL-93 in the new table is represented by an RF only for inventory and operating level and RL (Tons) are not applicable here since HL-93 is only a notional load.

5. There are a few times throughout the manual where the statement “…the initials of the reviewer shall be placed on every sheet of the calculations.” Are electronic initials sufficient for “hand-calcs” using programs such as MathCAD or are wet initials required?

Response: Any kind of initials will do.

6. Regarding the new vehicles I would like to make sure that what I’ve concluded from the new guidelines is correct:
a. RI-BP3 is a new vehicle
b. RI-BP4 was previously RI-OP2
c. RI-OP2 was previously RI-OP3
d. RI-OP2 was previously RI-OP4

Response: All the above correct except for d.
d. RI-OP3 was previously RI-OP4

If you have any further question, let us know.

Here are the answers to your questions: (AI)


1) On Page 6 Table #1 the HL-93 and Specialized Hauling Vehicles (SU4,SU5,SU6 & SU7) are listed as AASHTO Legal loads. Is there any reason?

Answer 1: The Specialized Hauling Vehicles are considered part of the legal loads per the MBE and FHWA regulations.

2) Response: The color of the cover is not determined only by the legal load vehicles but by any rating and is independent of the controlling limit state and is strictly based on the controlling rating factors regardless of what controls the posting.

Does this include also HL-93 vehicle?

Answer 2: The HL-93 is a notional load and not an actual vehicle, and should not be considered in deciding the color of the cover.

3) Could you clarify which legal loads are we going to use for posting analysis?

Answer3: Page 24 Rating Table includes Posting Column, the posting values should be calculated for every single vehicles listed in that table except for

HL-93. RIDOT will decide later how the posting signs will be carried out across the state.

After all of this we still noticed one change that the new RI-BP4 is not the same as the previous RI-OP2 with changes in the spacing between the last two axles previously 4'-6" and now 4'-3".

 
You are right the RI-BP4 was previously RI-OP2 and the rear axle spacing should be 4’-6”. It was a typing error in our latest manual and we will correct.