The connection shown on the typical details was developed based on research for deck bulb tee beams. The headed reinforcing bars were found to be fully developed with the specified lap length and bar spacing. The headed bars were placed just below mid-depth in order to provide both positive and negative moment capacity. The slight lowering of the bars was done to provide slightly more positive moment capacity since the connection is mid-way between the stems (positive moment region).
The PCI Northeast committee felt that it is important to use only one layer of bars in order to reduce fabrication costs. Multiple rows of bars can be used; however the costs will increase.
The design of the connection should be based on the moments generated using a standard AASHTO strip method. The deck can be designed by treating each stem as an individual beam with the deck spanning between stems. Once the positive moment is calculated at the joint, the section can be checked assuming that the projecting bars are fully developed. The reinforcing shown on the typical details should work for most scenarios; however it should be checked for each design. If more moment capacity is required, the bars can be lowered to achieve more moment capacity.