Rip rap, Gabions and Stone slope protection|erosion control|

Riprap and slope protection are of the following types:

  1. Boulder apron placed with and while not wire mesh gabions.
    Stone/boulder pitching (riprap) on slopes, placed by hand with filter layer.

Materials for Riprap

  1. Riprap design
    Riprap design
  2. Stone for apron and pitching shall be sound, hard, durable, and fairly regular in form with a minimum of one facet broken. Stone subject to marked deterioration by water or weather shall not be used.
    All stone shall be taken from approved sources. The stones shall be fine boulders or rock, production of granite, quartzite, or similar materials having a selected gravity of a minimum of two.4 and a compressive strength of a minimum of four00 kg/cm2
    Stones for apron and pitching shall weigh a minimum of forty weight unit. Spalls shall be minimum twenty five millimetre size and appropriate to fill voids in apron and pitching.
    The material for filters shall comprises sound gravel, stone or brick ballast and coarse sand, For one layer filter the compacted thickness of the filter shall not be but one hundred fifty millimetre. For a multi layer filter, the compacted thickness of every layer filter material shall not be but a hundred and fifteen millimetre.
    Gabions and city Mattresses
    The iron wire shall fulfil the specification of IS 280 or bachelor’s degree 443.
    The Minimum weight of metallic element coating per unit space of uncoated wire surface shall be as given below:
    Nominal diameter of wire (mm) 2.2 2.7 3.0 3.4 3.9
    Nominal weight of coating gm/cm2 240 260 275 275 290
    The lastingness of the wire shall be between 40-55 kg/mm2
    Gabions shall comprises wire netting double knotted to create a sq. mesh of a hundred millimetre x a hundred millimetre and therefore the stone for filling gabions shall be onerous clean stone between ten cm and twenty five cm. The gauge of the GI wire are ten SWG or as nominal. The gauge if GI wire used as Selvedge wire are of seven SWG.
    Box gabions shall have wire frames firmly tied to the netting at the sides of the box. Before inserting any orders for gabion baskets, the Contractor shall submit for the Employer’s Representative’s approval, full details of the hampers he proposes to use.
    Apron for Riprap
    General:
    This work shall comprises egg laying boulders directly, or in wire crates on the bed of rivers or where directed by the Employer’s Representative for cover against scour. The thickness and form of aprons shall be as indicated on the drawings or as set by the Employer’s Representative. The surface on that the apron is to be arranged shall be levelled and ready for the length and breadth as shown on the drawings.
Riprap design for protection of structure.
Riprap design for protection of structure.
A. Laying Boulder Apron:
To ensure regular and orderly disposition of the total meant amount of stone within the apron, guide walls in masonry shall be engineered a few meter thick and to the total height of the desired thickness of the apron at intervals of thirty meters right along the length and dimension of the apron. at intervals these walls, the stone then shall be hand-packed.

Laying Wire Mesh Gabions within the Apron:
Before putting in position, the gabions shall be stretched to their full size and shall be wired the least bit edges.
Each row of gabions shall be wired to the neighboring row at the highest and bottom edges and at the corners.
Each gabion shall be fastidiously packed by hand with stone thus placed on minimize voids. the highest layers of stones shall be placed with their flattest sides upmost to supply a swish surface for putting the lid. The gabions shall be stuffed twenty five metric linear unit on top of the highest so the lid may be tightly stretched over the stone. The lid shall be wired all spherical.
Adjoining rows of gabions shall initial be half stuffed to confirm that the perimeters of the mesh don’t bulge.
Care should be taken that the gabions don’t seem to be distorted throughout filling.
Gabions and mattresses shall be placed on prime of a filter material. In no case can or not it’s allowed to position gabions and mattresses directly connected with the soil.

Pitching on Slopes and riprap
General:
This work shall contains covering the slopes of guide banks, embankments and where directed by the Employer’s Representative, with stone, boulders or bricks over a layer of granular material referred to as filter to empty off oozing water and to stop erosion of the bottom materials by providing hierarchical material. The pitching shall extend from the most water level, together with allowance for wave action, if any, down and concerning thirty cm below the bed level or as per the drawings. The thickness of pitching shall be provided as shown on the drawings.

Construction Operations:
  1. Before birthing the pitching, the perimeters of banks shall be cut to the specified slope profile place up by suggests that of lines and pegs at intervals of three metres to make sure regular straight work and an even slope throughout. Depressions shall be stuffed and totally compacted.
    The filter granular material is to be arranged over the ready base and befittingly compacted to a thickness of a hundred and fifty metric linear unit or as nominal on the drawings.
    The lowest course of pitching shall be started from the toe wall and build up in courses upwards. The toe shall be in dry rubbish masonry (uncoursed).
    The stone/boulder pitching shall begin during a trench below the toe of the slope. Stone shall be placed by derrick or by hand to the specified length, thickness and depth conformist to the Drawings. Stone shall be set traditional to the slope and placed in order that the massive dimension is perpendicular to the face of the slope unless such dimension is bigger than the desired thickness of pitching. the biggest stone shall be placed within the bottom courses and to be used as headers for succeeding courses.
    When full depth or pitching may be shaped with one stone, the stones shall be arranged breaking joints and every one interstices between adjacent stones shall be stuffed in with spalls of the correct size and compact in with hammers to make sure tight packing.
    When there square measure 2 or additional layers the stones should be arranged to get the look thickness of pitching, masonry shall be used and stones shall be guaranteed.
    Measurement and Payment
    Measurement: The protection works shall be measured as set forth below:
    If directed by the Employer’s Representative for measuring the materials could ought to be stacked at website before birthing and zip further are going to be paid to the Contractor for this stacking.
    The wire mesh gabions (boulders and wire crates) are going to be measured in cube-shaped meters.
    The filter and stone/boulder pitching (riprap) are going to be measured on an individual basis in cube-shaped meters for every category of fabric.
    Preparation of base for birthing the flooring shall be deemed related to the work.
    For birthing apron, excavation up to a mean depth of fifteen cm shall be deemed to be enclosed within the main item and shall not be measured on an individual basis unless otherwise nominal.
  1. RipRap

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Rip rap, Gabions and Stone slope protection|erosion control|

RCC concrete construction |concrete constructor| A complete Analysis for Concrete Construction(step-by-step)| concrete-part second

RCC concrete construction |concrete constructor| A complete Analysis for Concrete Construction(step-by-step)| concrete-part second

 

 RCC concrete Construction 

Continued from part First >>

(Placing of Concrete)

RCC Concrete construction for Reinforcement Concrete(RCC) ,concrete block foundation,concrete residential construction,patio pavers, cement binder , road area unit complicated task ,there is a series of steps and rules followed for correct High strength RCC structure and for there sturdiness.

RCC concrete Construction
Continued from half 1st >>

(Placing of Concrete)
A. Concrete is placed solely within the presence of the Employer’s Representative or his authorised representative. when the surface has been ready satisfactorily, surfaces or construction joints upon that new concrete is to be placed, area unit flushed with a coat or neat cement grout or coated with a layer of mortar close to three cm thick. The mortar is that the same proportion of cement and sand because the regular concrete mixture, unless otherwise directed. The water-cement magnitude relation of the mortar is appropriate for putting and dealing within the manner herein nominal. The mortar is unfold uniformly and worked completely into all irregularities of the surfaces. Concrete then placed now upon the contemporary mortar. In inserting concrete against shaped construction joints, special contact with the surface of the joints area unit achieved by careful puddling and spading with the help of appropriate tools.

B. Retempering of concrete aren’t be permissible. Any concrete that has become therefore stiff that correct inserting can not be assured discarded and no payment are going to be created to the Contractor for such wasted concrete. Concrete ought to deposited altogether cases as nearly as practicable directly in its final position and not flow in an exceedingly manner to allow or cause segregation. Excessive separation of coarse aggregates in concrete, caused by permitting the concrete to fall freely from too nice a height or at too nice associate angle from the vertical, or to strike the forms or reinforcement steel, aren’t permissible and wherever such separation would otherwise occur, the Contractor ought to offer appropriate drop chutes and baffles to confine and management the falling concrete.

RCC concrete construction
RCC concrete construction

C. Except as intercepted by joints, all fashioned concrete placed in continuous horizontal layers, the depths of that typically not exceed fifty cm. The Employer’s Representative reserves the correct to want lesser depths of layers wherever concrete in fifty cm layers can’t be placed in accordance with the necessities of this specification. All intersections of construction joints with concrete surfaces which can be exposed to look at is formed straight and level or plumb, unless otherwise shown on the Drawings as ordered by the Employer’s Representative.

D. giant Blocks: In inserting Concrete in giant thick exposed spaces the Contractor ought to maintain the exposed space of contemporary concrete at the practicable minimum by initial build up the concrete to full breadth of structures and to full height of the elevate over a restricted space at one finish of the structure and so continued in similar progressive stages across the structure and so continued in similar progressive stages to the complete area of the structure. The slope fashioned by the unconfined edges of concrete is unbroken as steep as practicable so as to stay its space to a minimum. Concrete on these edges aren’t vibrated till adjacent concrete within the layer is placed except that it vibrated in real time once conditions square measure such the concrete can harden to the extent that later vibrations won’t absolutely consolidate and integrate it with a lot of recently placed adjacent concrete. Clusters of enormous mixture square measure scattered before new concrete is placed over it. Once placement of concrete has commenced during a structure, placement isn’t interrupted, unless adequate construction joints will be created.

E. Rain: Concrete isn’t placed throughout rains sufficiently significant or prolonged to scrub mortar from coarse mixture on the slopes of the location. throughout such rains mortar shouldn’t unfold on construction joints and diluted mortar already unfold square measure removed and replaced before continued with the work.

F. Buckets: Concrete buckets wherever used square measure capable of promptly discharging the low-slump concrete mixes such and therefore the merchandising mechanism is meant to allow the discharge of as very little as zero.35 M3 parts of the load in one place. Buckets square measure appropriate for attachment to and use of drop chutes wherever needed in confined locations.

G. Concrete around Openings: If concrete is placed monolithically around openings having vertical dimensions bigger than sixty millimetre, and if concrete in decks, floor slabs, beams, girders or alternative similar elements of structures if placed monolithically with the concrete of structures, the subsequent directions square measure strictly observed;

Placing of concrete is delayed from one to a few hours at the highest of openings and at all-time low of bevels below decks, floor slabs, girders or alternative similar elements of structure members once bevels aren’t such, however in no case is inserting be delayed ciao that the vibratory unit won’t without delay penetrate of its own weight into concrete placed before the delay. once consolidating the concrete placed when the delay, the vibratory unit penetrate and vibrate the concrete placed before the delay.
The last sixty cm or a lot of of concrete placed in real time before the delay square measure placed with as low slump as practicable and special care shall be exercised to result thorough consolidation of the
The surface of concrete wherever delays square measure created is clean and free from loose and foreign material once concrete is started when the delay.
Concrete placed over openings and in decks, floors, beams, girders and alternative similar elements of structures square measure placed with as low a slump as practicable and special care is exercised to result thorough consolidation of concrete.
H. Consolidation: every layer of concrete is consolidated to the utmost practicable density, in order that it’s free from pockets of aggregates and closes snugly against all surfaces of forms and embedded materials. In consolidating every layer of concrete, the vibratory head of the vibrator is allowed to penetrate and revibrate the concrete within the higher portion of the underlying layer. All concrete for major structures square measure consolidated with electrical or gas power driven immersion kind vibrators, operative at speeds of a minimum of seven,000 revolutions per minute once immersed within the concrete. Hand consolidation, exploitation slice bars, square measure utilized for minor structures at the Employer’s Representative’s direction. extra layers of concrete aren’t placed till the layers antecedently placed are compacted totally as such. instrumentation used for consolidating the concrete square measure subject to the approval of the Employer’s Representative.

Temperature of Concrete

RCC concrete construction
RCC concrete construction

 

RCC construction

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RCC concrete construction |concrete constructor| A complete Analysis for Concrete Construction(step-by-step)| concrete