ARMY TM 5-5420-212-10-1MARINE CORPS TM 08676A-10/1-1Section VI. ANCHORAGE - DOUBLE STORYThis section provides the information used to determine if anchorage is needed, types of anchorages, andprocedures for installation. The components used are listed in Appendixes D and E of this TM.6-15.BASIC CONSIDERATIONSa.The requirement for anchorage will be determined during site reconnaissance. Factors such as, slope offinished bridge, volume and type of traffic, and bank conditions will be used to determine if anchorage is required.b.Slope of Finished Bridge. The steeper the slope of the finished bridge, the greater the possibility thatanchorage is needed. Consider crossfall of bridge along with slope from end to end. Do not consider the above to meanthat completely level bridges will not need anchorages, as the volume and type of traffic and bank conditions must also beconsidered. Bridges constructed on solid banks or on packing may creep under a high volume of traffic (especiallyarmored, tracked vehicles). If anchorage is not installed, a bridge should be checked during crossing of traffic for any signof creeping. If creeping is detected anchorage should be installed.c.Volume and Type of Traffic. Heavy wheeled and tracked vehicles may cause the bridge to creep. This is theresult of impact loads against the end of bridge, and braking/accelerating on the bridge. Control of vehicle approachspeed and movement across the bridge will reduce these loads. High volume of medium to heavy vehicles in onedirection may cause creeping. Stop vehicles prior to impact on the end of bridge, and instruct drivers to maintain aconstant safe speed, not to shift gears, and not to make any sudden stops.d.Bank Conditions. Banks that will allow slow settling of the end of the bridge will probably reduce the amountof creeping. Firm, solid banks will increase the need for anchorage.e.Final Determination. After considering the basic factors, the final determination if anchorage is needed will bemade by the bridge commander. If anchorage is not installed, the bridge will be checked regularly for any sign of creeping.If detected, the severity of creeping will be determined, and anchorage will be installed if deemed necessary.6-16.TYPES OF ANCHORAGEThe types of anchorage used for MGB are Picket and Approach Guy.a.Picket Type. Consists of pickets driven into the bank along the outside of the bankseat beams. This type ofanchorage can be used for small (2E + 1 thru 2E + 12 bay) double story bridges. Picket type anchorage is installed afterthe bridge has been put on the ground at both ends, and before ramps are added. During crossing of traffic, check bridgefor any sign of creeping.b.Approach Guy Type. Consists of anchorage cables attached to holdfasts at the bank end, and to anchoragepins in the bridge at the other end. Four cables can be used at each end of the bridge. This type of anchorage must beused for bridges 2E + 13 bay and over, with or without reinforcement. It can also be used for small bridges (2E +1 thru 2E+ 12 bay).NOTEAnchorage installation should not Increase building time by more than one half of an hour.6-72
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