FOUNDATIONS OF MISSISSIPPI RIVER BRIDGE AT BATON ROUGE, LOUISIANA

THIS REPORT DISCUSSES PRINCIPALLY THE FOUNDATION EXPLORATIONS AND THE USE OF THE PRINCIPLES OF SOIL MECHANICS IN THE DESIGN OF THE PIERS FOR THE BATON ROUGE BRIDGE. TWO SERIES OF BORINGS WERE MADE. IN 1934, 2-IN CORES WERE TAKEN TO DEPTHS OF 200 FT. AND IN 1936, 35-IN. CORES WERE TAKEN TO DEPTHS OF 300 FT. FROM THESE BORINGS A PROFILE OF THE MATERIAL UNDERLYING THE BRIDGE SITE WAS MADE AND SAMPLES SECURED FOR LABORATORY STUDY. FROM THE CONSOLIDATION TESTS ON SAMPLES AND THE ESTIMATED LOADS TO BE IMPOSED BY THE PIERS ESTIMATES OF EXPECTED SETTLEMENTS WERE MADE WHICH WERE LATER FOUND TO BE IN SUBSTANTIAL AGREEMENT WITH THE OBSERVED SETTLEMENTS THUS FAR NOTED. THE INFORMATION SECURED FROM THE UNDISTURBED SAMPLES INDICATED THAT THE SOIL UNDERLYING THE PIER BASES IS CAPABLE OF SUPPORTING THE LOADS WITHOUT EXCESSIVE SETTLEMENT, AND THAT UNIFORM SETTLEMENT MIGHT BE EXPECTED. IT IS CONCLUDED THAT APPLICATION OF THE PRINCIPLES OF SOIL MECHANICS TO DEEP FOUNDATION PROBLEMS MAKES IT POSSIBLE TO DETERMINE IN ADVANCE THE MAGNITUDE OF THE SETTLEMENT TO BE EXPECTED AND TO PROVIDE FOR THIS SETTLEMENT, TO ANTICIPATE WITH SOME DEGREE OF ACCURACY THE AMOUNT OF SETTLEMENT TO BE EXPECTED DURING CONSTRUCTION STAGES AND TO FURTHER ANTICIPATE PROGRESSIVE SETTLEMENT OVER A PERIOD OF YEARS. FURTHER, IT IS POSSIBLE, AFTER ANTICIPATED SETTLEMENTS HAVE BEEN DETERMINED, TO ADJUST THE SIZES OF THE PIERS, OR BASE AREAS, SO AS TO GET PIERS OF APPROXIMATELY EQUAL SETTLEMENT. LOADING OF TEST PILES ALSO INDICATED THE POSSIBILITY OF THE APPLICATION OF THE PRINCIPLES OF SOIL MECHANICS TO THE DESIGN OF PILE FOUNDATIONS, ALTHOUGH IN THIS CASE THE NEED FOR CONTINUED RESEARCH IS POINTED OUT. /AUTHOR/