 Bridges are critical parts of the highway. The deck is the part of the bridge that receives a lot of wear and must be repaired quickly if defects appear. Holes in the deck can cause accidents. Also, the pounding of traffic can cause further damage to the deck. If reinforcing steel bars are exposed, they quickly rust and weaken the deck. The bridge must then be closed because it would be unsafe. It is very expensive to rebuild a bridge deck. For these reasons, it is important to perform good maintenance and quick repairs. This videotape will focus on the permanent repairs for partial depth holes and full depth holes. Partial depth holes are failures that do not go through the deck. A full depth hole is a failure that goes all the way through the deck. To repair partial depth and full depth holes, you will need the proper equipment. An air compressor with a light breaking hammer, not greater than 20 kilograms, and a blowpipe attachment to clean out the hole. A concrete power saw to cut the sides of the area to be repaired. A portable generator if you need electricity to operate the saw. A concrete mixer to prepare the concrete. And hand tools which include chisels, a trowel, a sledgehammer, wire brushes, a straightedge, a steel bar, stiff brooms, rods, shovels, buckets, and wheel barrows. For the full depth hole repair, you will need plywood forms and galvanized wire strong enough to hold the forms. You will also need wood to build the framework that holds the plywood at the bottom of the deck. A ladder will be needed in case the full depth hole repair is on a bridge where the bottom part of the bridge deck is accessible with a ladder. For the concrete use a high early strength cement. If not available use other approved cement. You will also need clean aggregate with angular stones no larger than 2 centimeters. Clean sand and water and a curing compound or fabric material to cure the concrete patch. Some linseed oil will be needed to grease the form. Let us look quickly at the procedure to repair partial depth and full depth holes. Step one, place the traffic control devices. Step two, inspect the damaged area and mark the limits of the repair. Step three, prepare the hole. Step four, prepare the concrete. Step five, place and finish the concrete. Step six, clean up the work area. Step seven, remove the traffic control devices. Now let us look at the work steps in detail. Step one, place the traffic control devices. For this repair you will have to close one traffic lane. Refer to the IRF traffic control videotape for more information. Park the truck inside the closed traffic lane and behind the barricade to protect the workers. It should be positioned to allow sufficient space for workers and equipment. Step two, inspect the damaged area and mark the limits of the repair. Tap or pound the deck area lightly with the end of a steel bar. If the concrete below the deck surface is damaged, the bar will produce a hollow sound. Continue to tap the defective area by working in a radius away from the hole until the hollow sound is replaced by a solid sound. Mark the area with chalk. Make the marked sides parallel and perpendicular to the center line of the bridge. The limits must be on good concrete. Mark your limits five to seven centimeters beyond the damaged area. Step three, prepare the hole. To start, cut along the marked edges. Use the concrete power saw to make vertical cuts about two centimeters deep. Do not cut the steel bars and do not saw beyond the corners. This could soon spoil out. If necessary, chip out the corners with a chisel and hammer. Next, break up and remove damaged portions of the concrete. Use a light jackhammer. Do not let the bit touch the reinforcing steel since it will break the bond in the area where the concrete is still good. Remove the chipped, loose material out of the way. Use compressed air to remove loose material under the exposed steel bars. If the damage extends down to the reinforcing steel or below it, make sure a space of at least two centimeters, which is slightly more than the width of a finger, exists around the reinforcing steel so that a good bond will be made between the new concrete and the steel. Then, clean the exposed reinforcing steel bars and the concrete surface inside the hole. Use a wire brush to scrape away any rust. The steel must be clean for a good bond with the patching mixture. Clean out the loose particles and sweep them away from the defective area. Dispose of them in an approved area. Use compressed air to blow all fine particles out of the hole. Inspect the hole carefully before any concrete is placed in the hole. Make sure that there is no loose material in the hole or rust on the steel bars. Also, use steel wire to retie the steel bars if necessary. If the damaged area goes through the deck, you must build and place a form to hold the concrete mixture. Make sure that the surrounding concrete and the steel bars are in good condition. If steel bars must be replaced, consult your maintenance engineer. Use wood to build the framework. Place the finished framework on top of the deck, centering it around the hole. Then, grease the wooden form with linseed oil. This will permit the new concrete to be free from the wooden form. Place the greased form on the bottom part of the bridge deck. Use a ladder if the bridge is accessible from under the bridge deck. If you cannot get to the underside of the bridge, build the form in sections. Slip each section between the steel bars to the bottom part of the bridge deck and attach them to the framework. The form should be properly wired and tied to the wooden framework. Center the wooden bar that holds the wires so that the concrete can be poured easily. Step 4. Prepare the concrete. Usually, the concrete is made with high, early-strength cement, so the bridge can be opened to traffic sooner than with regular cement. If not available, you can use regular Portland cement. Do not mix the concrete too far in advance because it will set up very quickly. Also, use only washed, angular aggregate, clean sand, and clean water. Be sure to check with your supervisor for proper proportions of cement, aggregate, sand, and water, as well as the use of special curing additives if needed. Step 5. Place and finish the concrete. To start, pre-wet the hole to make a tighter bond between the old concrete and the new concrete. Place the concrete in controlled layers so that the mix covers the exposed area without air gaps. Use your shovel to work the concrete carefully around and under the reinforcing steel and into the corners to eliminate voids. Use a trowel to finish the surface of the repair. It should be level with the existing deck surface. Check the surface with a straight edge. Use a broom to texture the surface. Drag it lightly in the same direction as the surrounding concrete surface. Lay a damp cloth over the patch to promote proper curing of the concrete. If a high, early-strength cement or a special curing additive is used, cure the patch at least two or three hours before opening the area to traffic. Otherwise, it will take three to four days for the patch to dry properly. At this time, clean the hand tools so that the concrete will not harden on them. Step 6. Clean up the work area. Start while the patch is curing. Sweep all loose material into piles. Dispose of this material at a site approved by your supervisor. Load all tools, equipment and unused material back on the truck. Check the patch to make sure the cloth remains damp. Check the patch. When the patch is cured, remove the cloth and framework before opening the repaired area to traffic. Step 7. Remove the traffic control devices. Pick them up in the reverse order of their placement. Let us review the partial depth and the full depth whole repair procedures for concrete bridge decks. Step 1. Place the traffic control devices. Follow approved procedures to make the work site safe while the repairs are being performed. Step 2. Inspect the damaged area and mark the limits of the repair. Mark your limits five to seven centimeters beyond the damaged area in good concrete. Step 3. Prepare the hole. Cut along the marked edges. Break up and remove damaged portions of concrete. Clean the exposed reinforcing steel and remove any loose material. If you are repairing a full depth hole, build and place the form. Step 4. Prepare the concrete. Do not mix it too far in advance because the concrete will set up very quickly. Step 5. Place and finish the concrete. Place the concrete in controlled layers. When you finish, place a damp cloth over the patch to promote proper curing. Step 6. Clean up the work area. Sweep all loose material into piles and dispose of that loose material properly. Step 7. Remove the traffic control devices. Pick them up in the reverse order of their placement. Follow these procedures for repairing concrete bridge deck holes to ensure long-lasting repairs.