LOAD CAPACITY OF SOLID-SECTION WOODEN BEAMS AFTER LONG-TERM MOISTURE

Abstract

Many wooden elements and structures are directly affected by the aquatic environment, which includes both fresh and salt water. These include bridge structures, shore protection and hydraulic structures, sea piers and many others. Including elements that work on bending are subject to such an impact. The humidity is more than 30%, which makes it difficult to calculate wooden elements and structures according to current regulatory documents

For experimental research, 12 beams of solid cross-section with dimensions of 50x80x1650 mm with a humidity of 12% were manufactured. The bending elements are made of coniferous wood of pine and spruce. Then 8 manufactured beams were soaked in fresh and salt water environments in special baths for 180 days. The humidity of the wood after immersion was more than 30%. Testing of soaked and unsoaked bending elements was carried out in a special experimental setup under a single short-term load. Deformations were measured using strain gauges, deflections using inclinometers.

Experimental studies of bending elements after prolonged moistening with a single short-term load were carried out. Based on the results of experimental studies, the bearing capacity of unsoaked beams was 14.1 kN for pine wood and 10.7 kN for spruce. After soaking in fresh water, the indicators decreased to 8.0 kN for pine and 6.6 kN for spruce. Under conditions of exposure to salt water, the bearing capacity was 8.9 kN for pine and 5.8 kN for spruce, respectively. After soaking in fresh water for 180 days, the load-bearing capacity of solid-section beams made of pine wood decreased by 1.76 times, and of spruce wood by 1.62 times compared to beams with a humidity of 12%. After exposure to salt water, this indicator decreased by 1.58 times for pine and 1.84 times for spruce. The features of the destruction of soaked and unsoaked experimental beams are presented.