Riprap / Stone Pitching Protection Sample Clauses
The Riprap / Stone Pitching Protection clause sets requirements for the installation of protective layers of stone or similar materials to prevent soil erosion and stabilize embankments or slopes. In practice, this clause outlines the specifications for the size, placement, and compaction of stones, as well as the areas where such protection must be applied, such as riverbanks, drainage channels, or road embankments. Its core function is to ensure long-term structural stability and prevent damage from water flow or weathering, thereby reducing maintenance needs and safeguarding infrastructure.
Riprap / Stone Pitching Protection. The quality of stone shall be as specified in Clause 4.01. The stones for rip-rap shall be a natural, big size, of irregular shape having a minimum weight of 30 kg each and minimum thickness of 20 cm when measured at the thinnest section. At least 60% of the stones shall have a minimum weight of 40 kg each, with minimum volume of 0.03 m3. The stone shall be laid by hand, to the required lines and grades and to the thickness shown on the Drawings and placed so that it will thoroughly tamped, or driven into place. The space between the larger stone shall be filled with spills of suitable size driven to face, varying not more than 60 mm from the required contour. Before placing riprap rocks, the bedding which consists of well-graded sand shall be provided with the required thickness shown on the drawings or as directed by the Engineer. Such sand bedding shall be compacted thoroughly by mechanical tampers. The rocks in the riprap shall then be dumped and graded off on such sand bedding. Pitching will be used where a finished horizontal or inclined surface is required. It shall consist of hand placed stones, with spalls wedged into the interstices to produce an even surface, without projection above the neat lines shown on the Drawings. Care shall be taken to ensure that the stones are well bedded and the percentage of spalls shall not exceed forty percent (40%) of the total rock volume. Pitching on slopes shall be built upwards from the toe, unless otherwise directed by the Engineer. A coping consisting of large flat stones shall be laid along the top of stone pitching on slopes to produce a firm edge.