- March 18th, 2015, 12:10 pm
#73377
That article was specific to masonry structures (ie, vertical brick walls). For concrete pavements there is no practical distinction between "horizontal" and "vertical". For trafficways, there is "longitudinal" (in the direction of traffic) and transverse (perpendicular to traffic), but all pavement is laid roughly horizontal.
When designing the jointing for concrete pavements or sidewalks, the contraction (cut) joints are placed in order to provide a weak spot in the concrete. The nature of the material is such that the concrete WILL crack; contraction joints help to control where those cracks will occur.
As the concrete expands and contracts, it does so in all directions, not just in the direction of the traffic flow. Because of this movement, you can typically expect cracks to occur at specific intervals. The interval of cracking is based on the thickness of the pavement primarily (thicker pavement can resist cracking for longer distances). Because the concrete is expanding in both directions, the "panels" between cuts need to be roughly square. Very rectangular panels will correctly control the cracking in one direction, but will often develop an unsightly crack down the middle in the other direction.
Looking at these two walkways, notice that the freshly poured concrete on each side of the state line strip is roughly one third the wide of the total walking area on the bridge's walkway. Therefore, you'll need approximately three times as many cuts to keep the panels "square" on the state line side than we saw on the bridge side.
I hope this helps clear up any issues for you. Please let me know if you have any other pavement questions.
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