ACCELERATED BRIDGE CONSTRUCTION

Ross Clark Circle Bridge Slide

Dothan, Alabama

231 431

231

Ross Clark Circle (west side)

� US 231

� Built in 1950s

� Divided Four Lane

� Average Daily Traffico design – 5,000 o current > 40,000o 20 year ≈ 73,000

Beaver Creek Culvert

� 3 BBL 10’(↔) x 6’ (↨)

� 155 ft long

� 20’ fill

� Structurally Deficient(severely cracked)

� Opening has immersed

UTILITIES WATER

SEWER

OVERHEAD

ELECTRIC

TELEPHONE /

CABLE

Exit End

Entry End

Contractor provides

engineered design

Temporary Shoring Boxes and Falsework

Temporary Shoring Boxes

Used to construct the

permanent bridge

abutment piles and cap

seats

Temporary Falsework

Used to construct the new bridge

superstructure adjacent to the

permanent structure location and

for support during the bridge slide

Temporary Falsework

Temporary Shoring Boxes

� Cost effective

� Used material that was

readily available to McInnis

Construction

� Could be installed quickly at

the project site

� Could be de-constructed

� Could be re-used on future

projects

In order to ensure

proper geometry

controls and check

constructability, McInnis

Construction set up a

pre-fabrication site at

their home office to

verify the temporary

shoring box geometry

and fit-up, pick weights

and crane reach

requirements,

fabrication steps,

transportation

requirements, and de-

construction sequence

Pre-Fabrication Site

Thompson Engineering coordinated the AASHTO

LRFD design of the temporary shoring box with

McInnis Construction in order to optimize

construction means & methods.

Lay-Down Area

Construction activities

continued concurrently as

the shoring boxes were built

in the Lay-Down area.

A two phase traffic control was used to maintain traffic during excavation and installation of the shoring boxes. The first phase shifted traffic to the inside with excavation on the outside.

A plan note required existing traffic to be maintained during peak hours, therefore McInnis Construction installed the shoring boxes during the weekend including nighttime work to minimize impacts to traffic.

To stay within the crane capacity the upper lid and side sill plates were erected separately.

Backfilling and approach roadway asphalt being completed.

Corner piles and timber wingwallswere installed to support the approach roadway embankment.

Phase two traffic control shifted traffic to the outside while construction activities were repeated on the inside.

Excavation continued on the inside while traffic was maintained on the outside.

Shoring boxes being erected and set in the trench.

The last of the four shoring boxes being set adjacent to traffic.

Inside excavation.

Pile Driving Preparation

After the shoring boxes were installed, pile layout and geometry control checks were made prior to pile driving.

A similar inside/outside traffic control was used to drive the piles after the upper lids of the shoring boxes were removed. Additional falsework piles were driven on the outside.

After the piles were installed the abutment cap seat was constructed.

Temporary Falsework

Temporary falsework was installed adjacent to the new bridge location to support the new superstructure in preparation for the bridge slide.

The BT-63 inch precast prestressed concrete bulb-tee girders were erected adjacent to the new bridge location on the falsework.

� Shoring system needs to be wrapped with plastic or filter blanket to stop intrusion of sand from backfilling around the box.

� Top sill plate on sidewalls needs reinforcement/stiffness for when asphalt is placed adjacent to it. Sill plate deformation caused the top lid to become extremely difficult to lift and place during lane closure construction.

� Shoring system was designed heavy for reusing purposes. However, we need it to be lighter or have a larger crane so we could set a more completed section during lane closure construction.

� Backfilling the shoring boxes after excavation took the longest time. More ways to improve logistics on job site.

� Prefabricating the boxes worked good. Need to improve on the shipping dimensions and time to fabricate on the job site.

� Owner & Project Designer: Alabama Department of Transportation

� Contractor: McInnis Construction

� Construction Engineer: Thompson Engineering