Bruce,

This afternoon, we discovered that the proposed grading at the southwest corner of the Bella Lane Bridge will be high enough to partially cover the top of the abutment cap. (See Abutment
Grading attachment for detail.) TxDOT guidelines indicate that the rip-rap immediately in front of the abutment should be no closer than 1'-6" to the top of the abutment cap. This allows
for future inspection and repair of the box beams, bearing pads, and carrier pipes. We recognize that this large a change may be very costly to accommodate and are therefore recommending
that the proposed grades in this area be adjusted downward to accommodate a minimum dimension of 9" from the top of the abutment cap to the rip-rap. This should allow sufficient space
for inspection. Please inform us when revised grading can be provided.

 

It should be noted that we are calculating the elevation of the top of the abutment cap based on our interpretation of your grading plan. We have attached another sketch (Cross Section.pdf)
that shows how we used your data. If we have misinterpreted your plans, please let us know. Perhaps that will have a positive effect on this issue.

 

Thanks,

Eric

 

Eric S. Christiansen, P.E., SECB, LEED AP

Senior Structural Engineer

 

	

	
HALFF ASSOCIATES, INC.

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