Construction

Indiana Department of Transportation SEP 14 Report Alternate Pavement Type

Appendix F US 24 (IR-30162)

Seven (7) Contractors participated in the bidding (6 PCCP options and 4 HMA options were bid) and all bids were below the engineer's estimate. Three (3) Contractors participated in both pavement type pay options.

INDOT provided the following pavement design thickness for mainline of this project:

1. 10.5 inches of PCCP or
2. 13.5 inches of HMA.

Bid Analysis Summary

The low bid amount, out of all 7 bids, was for HMA pay items option (Bidder A) and after adding PW cost of HMA and PCCP to the respective pavement type options, PCCP pay items option was the low bid (Bidder A). PCCP pay items option of Bidder A was awarded for this contract. The PW cost factor affected the outcome of the bidding.

INDOT compared the estimated cost with actual low bid costs of both pavement types. The following table shows the cost comparison with low bid of those pavement items that were relative to the mainline pavements and relative to this alternate bid for pavement type. All other items in the bids were common to both types of pavement option.

The above table shows that pavement item bids are all lower than or equal to the estimates used in evaluation, but on HMA the majority of the items are higher than the estimates. This indicates that a true cost saving was realized by INDOT in this process.

The table below compares some common HMA items found in both PCCP and HMA options to check for unbalanced bids. These bids appear to be consistent and no anomalies were found.

Conclusion

INDOT did not realize a saving immediately, at the bid opening, (HMA Low Bid - PCCP Low Bid = -$439,966.77). However after using the Bid Analysis amounts (after PW costs applied), INDOT saved the tax payers approximately $115,826.63 over the 50 year service life of the pavement. These savings include the reduction of INDOT's in-house cost of approximately $8,000.00 for approximately 80 hours of additional time spend by designer to developed two typical section sheets, design work, quantity calculation, and two cost estimates. The time spend by INDOT Contract Section were determined negligible.

The PW cost for future maintenance did impact the bids and which contractor received the contract. INDOT believes using this process of alternate bids for pavement type selection on this project was very successful.

PW of Future Maintenance of the Pavement IR-30162 (US 24)

PW of HMA Option = $1,475,368.14

PW of PCCP Option = $919,579.74

PW = F [1/(1+i)ⁿ]

Where: F = Future Construction Cost
i = Discount rate (4%)
n = Number of years from year zero