SUITABILITY TESTING: TRIALS OF NEW TYPES OF ABSORBING NOISE PROTECTION WALLS FOR USE ON ROADS

EIGNUNGSPRUEFUNG: ERPROBUNG NEUARTIGER ABSORBIERENDER LAERMSCHUTZWAENDE FUER DEN EINSATZ AN STRASSEN

THE SUITABILITY TESTING COMPRISES: (1) ESTABLISHMENT OF THE NOISE LEVEL DECREASE WHICH CAN BE OBTAINED IN PRACTICE; (2) DETERMINATION OF THE RESIDUAL REFLECTION OF VARIOUS DESIGNS AFTER LONG-TERM USE; (3) EFFECTS OF WEATHERING, ROAD DIRT AND DE-ICING SALT; (4) EFFECTS OF NOISE PROTECTION WALLS ON ROAD TRAFFIC;(5) CLARIFICATION OF POINTS OF DETAIL. TWO WALL SYSTEMS ARE TO BE USED FOR THE TESTS; THESE ARE OF DIFFERENT DESIGN BUT HAVE A GUARANTEED OPTICAL AND CLOSED ACOUSTIC EFFECT. BOTH SYSTEMS ARE BUILT OF STEEL WITH CONCRETE FOUNDATIONS AND PLASTIC WALL ELEMENTS. THE TEST WALL IS 200 M LONG AND 4 M HIGH, 50 M AWAY THERE IS A NOISE REDUCTION OF ABOUT 11 DB(A), AVERAGE NOISE FLUCTUATION IS REDUCED FROM ABOUT 13 DB(A) TO ABOUT 7 DB(A) (AT THE HEIGHT OF THE FIRST RESIDENTIAL LEVEL). AT 12 M HIGH THE NOISE REDUCTION IS STILL 8 DB(A). THE LANE BEHAVIOUR OF VEHICLES IS NOTICEABLY AFFECTED BY THE WALL WHICH IS 2 M AWAY FROM THE PARKING LANE, BUT THIS DOES NOT CONSTITUTE A HAZARD. STUDIES ARE TO BE MADE OF WEATHERING, POLLUTION AND NEGLECT OF THE PROTECTIVE ACTION, AND COMPARISONS ARE TO BE MADE WITH SMALL SECTIONS OF WALL MADE OF OTHER MATERIALS. SUPERSEDES IRRD RESEARCH PROJECT NO 56682.