Wednesday, October 12, 2011

Retaining wall clasification after the used material

            Using the material as criteria for a clasification we have the following retaining wall types:

  • Lumber retaining wall,type of wall that can be also: 
  1. anchored :-very popular due to instalation ease and lower material cost
-can be easily manufactured using recycled timber from an old structure framing
     -is commenly used in lanscape areas
      -the required length and spacing both vertical and horizontal of the anchors are calculated  based upon the wall height,lateral earth pressure and surcharge loading
     -the anchors("deadmen") are attached to the face timbers by spices and/or drift pins

    2. crib-wall: -very similar to the anchored lumber retaining wall in terms of ease and lower   material cost and technique  of assembly( members attached together by means of spikes and/or  drift pins);
    -better suited for areas where adequate space is not available or where the imposed  loads  are expected to be greater.
    - is constructed as an interconnected box with all sections working together to support   the intended loads. 
    -also commonly used in landscaped areas.
    3.wall-post and lagging-made of wooden posts and wooden laggings;
    -the posts can be installed with  a footing depth depending of the nature of the soil(even without a footing);
    - specially suitable when space and time (very fast construction needed) constraints are present;
    - can be also used as a wind barrier .

    -an example of a study case calculation for such a structure can be accesed here !
    •  Steel retaining wall,such as:
    1.cantilever sheet pile:-where STEEL SHEETS are used as vertical members embedded into the ground     to  resist lateral soil pressure through cantilever action;
      -usually used to retain noncoeziv soils as sand and gravel.

    2.steel soldier pile with concrete or lumber  lagging:-build with vertical I-SECTION STEEL POSTS  embedded  into the ground at regular spacings and horizontal CONCRETE/LUMBER LAGGINGS are placed between the steel plange members to retain soil.
    3.anchored steel sheet pile-where STEEL SHEETS are used as vertical members embedded into the ground     to  resist lateral soil pressure through cantilever action,but they are also pinned using cables or other stays wich are anchored into the rock or the soil behind it.
    4.anchored steel soldier pile-similar to the anchored steel sheet pile but insted of the steel sheets are used soldier pile. 
    • Concrete retaining wall such as:
    1.cantilever-constructed of reinforced concrete and it supports backfill soil by a cantilever action;
    -the cantilevered stem portion is fixed at the bottom and is free at the top;
    -the base slab serves as a fixed support and prevents against sliding and overturning;
    -there is an option to install a key at the bottom of the base slab to ensure further safety against sliding;
    -these walls provide prolonged durability and serviceability;
    -they are widely used due to their ease in construction and cost-effectiveness.

    - for an in depth analysis on how to proper design such a wall click here or here ! 
    2.gravity:
    -is constructed using mass concrete placement and generally without reinforcement,but sometimes with a slight  reinforcement placed where the concrete is porred in different stages;
    -the support of backfill and other imposed loads on these walls is provided by the sheer weight of the unit,is wide at the base and it tapers towards the top;
    -the overturning moment acting on this type of wall is counter-balanced by the resisting moment on account of the self-weight of the wall.
    3.crib-wall:
     - is an assemblage of individual concrete members of particular standard sizes,is generally used for lower backfill heights, in areas where horizontal space is limited, and where foundation excavations are more difficult( can be constructed at multiple heights along any cross-section)
    -the strong interlocking feature between individual crib members provides good stability to the overall structure;
    -the positive drainage of water from the backfill material through the gaps between members alleviates the need for a separate drainage system,but the minimum construction time, cost-effectiveness and less embedment depth make this type of wall popular for many different applications.
    4.butressed-(reinforced/unreinforced):
    -is a special type of Cantilever Retaining Wall with additional support in the form of buttress which are perpendicular to the retaining wall and are monolithic with the structure;
    -is usually used  against heavy lateral loads,it  can support a greater height of backfill;
    -depending on the height of the backfill and possibility of surcharge and/or possible seismic activities some reinforcement can be added to increase  its structural strength.
    • Masonry retaining wall such as:
    1.reinforced cantilever:
     -this type of retaining wall assembly mainly consists of standard masonry blocks reinforced with steel and a core of concrete;
    -these walls are similar to concrete cantilever retaining walls in shape and also behave in much the same manner.
    -for a in depth presentation on how to proper design such a wall please follow this link 

    2.mass block segmental gravity retaining wall:
    -is constructed from interlocking, dry-stacked (without mortar), precast block elements of standard shapes and dimensions, which are arranged in a running bond configuration;
    -it  resist destabilizing forces due to retained soils solely through the self-weight and embedment of the block elements so there for this wall is used for relatively low-height walls.
    3.mass block retaining wall reinforced-
    -this type of retaining wall consists of precast block elements of standard shapes and dimensions with interior holes which act as keys ensures bondage between the elements and give stability to the whole wall system;
    -this wall also has provisions for reinforcement in the form of small precast holes through which steel rods can be inserted.

    -for a in depth analysis on how  to proper design such a structure click here !
    • Special retaining wall structure:
    -TERRACED RETAINING WALL-CONCRETE
    -TERRACED RETAINING WALL-MASONRY
    -TERRACED RETAINING WALL-LUMBER-
    - TERRACED RETAINING WALL-STEEL






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