Geomembrane from Feicheng Lianyi Engineering Plastics Co Ltd

Application:

Earthwork dam, rock-fill dam, masonry dam and concrete dam; horizontal impervious blanket of embankment and dam front, vertical impervious barrier of foundation; tailing dam, dam body and reservoir region of sewage reservoir; construction cofferdam; canal, liquid bath (pit, coffin pit); waste storage; seepage control lining for subway, basement and tunnel; roadbed of speedway and railway; salting prevention of roadbed and other foundation; waterproofer of swelling soil and collapsible loess; roofing leak resistance.

Products: Two-side seepage control membrane and one preventive geotextile; one-side seepage control membrane and preventive geotextile.

Width: 4-6m.

Specification: membrane thickness 0.2mm-0.8mm; protective geotextile 100g/m2-800g/m2 (produced by our factory, conforming to the related national standard).

Table: Basic Technological Requirement：

SI No.	Items	Indices	Allowance, %
1	Mass-area ratio, g/m2	According to design or contractual specifications	-10
2	Width, cm	According to design or contractual specifications	-1.0
3	CBR bursting strength, KN	According to design or contractual specifications	-5
4	Breaking strength 1)，KN/m	According to design or contractual specifications	-5	Vertically and horizontally
5	Tearing extensibility %	Adherence to specification	30～100	Vertically and horizontally
6	Ripping strength *, KN	According to design or contractual specifications	-8	Vertically and horizontally
7	Stripping strength **, N/cm	6	Not below the standard	Vertically and horizontally
8	Resistance to hydrostatic pressure, Mpa	According to design or contractual specifications	Not below the standard
9	Permeability coefficient, cm/s	According to design or contractual specifications	Adherence to specification

* For the strength requirements of common short-fiber needling nonwovens/polyethylene composite geomembrane, see Table below

** If the sample is tested hard to predict its stripping and not beyond the high strength base material and membrane material, it will be regarded as qualified one.

Table: Strength Standard for Short-fiber Needling Nonwovens/Polyethylene Composite Geomembrane：

Mass-area ratio	400	500	600	700	800	900	1000	Remark
Strength requirement\membrane thickness, mm	0.25～0.345			0.3～0.5
Breaking strength, KN/m 5		7.5	10.0	12.0	14.0	16.0	18.0 Vertically and horizontally
CBR bursting strength, KN 1.1		1.5	1.Strength requirement\membrane thickness, mm 9	2.2	2.5	2.8	3.0
CBR bursting strength ，KN   1.1		1.5	1.9CBR bursting strength, KN 1.1	2.2	2.5	2.8	3.0

Note: When the practical specification is between the neighboring specifications in the table, the related check indicators will be calculated according to the interpolation method; if the product specifications is beyond the table given scope or it is with other process or construction, the check indicators carry out the design or negotiated by the supplier and demander.

What is Steel Fiber Reinforced Concrete?

Over many years, many research work performed to render concrete with flexural and tensile strength with its natural high compressive strength. The result is reinforced concrete having both longitudinal steel to provide bending and torsional strength and transverse steel (stirrups) to provide shear and torsional strength in flexural members. In case of compression member with longitudinal and transverse steel (tie or spiral) are used to provide compression plus bending strength. now-a-days short length steel wire or thin steel sheet are used to increase flexural strength, crack resistance and explosion resistance.

This special reinforcement is called steel fiber and the resulting concrete is steel fiber reinforced concrete. This type of concrete is widely used in abrasion suspected wearing surface.

The standard size and shape of steel fibers and their amount to be added in concrete mass are listed in the table below:

Fiber shape	Length, mm	Width, mm	Dia, mm	Thickness, mm
Steel wire having low carbon content	10 – 60	---	0.25-0.75	---
Steel flat sheet	10 – 60	0.25-0.90	---	0.15-0.40

This is to note that increase of strength properties is dependent on shape of fiber, quantity of fiber in the concrete mass and the type of fiber materials. How fiber are mixed in concrete mix is discussed in the post “HOW ARE STEEL FIBER USED IN CONCRETE?”

What are the Lateral Loads Considered in Raft Foundation Design?

In this post we will highlight ACI committee 336 recommendation for considering loads for combined or raft foundation - for these post lateral loads. At first we will know what vertical effects of horizontal loads are. These are:

a. Vertical effects from lateral loads F_vh

b. Vertical effects from wind loads, W

c. Vertical effects from earthquake loads that are found by simulating earthquake, E

Of them vertical effects from lateral load F_vh can consists of:

1. Water pressure

2. Earth pressure

3. Load like surcharge pressure, fill pressure

4. Differential settlement, differential creep, differential temperature and shrinkage effects of concrete.

Now we will know about overturning moment. They are of following form:

a. The moment that try to overturn the foundation due to simulated earthquake forces, ME.

b. The moment that try to overturn the foundation due to vertical effect lateral loads(Fvh) and termed as MF

c. The moment that try to overturn the foundation due to explosion, wind or similar forms of lateral loads, termed as MW.

d. The moment that try to overturn the foundation due to dead load of foundation with superstructure, D0. These loads may include buoyancy effects, if any, that are resulted from submerged portion or that portion supposed to be have future submergence.

e. The moment that try to overturn the foundation due to loads from unsymmetrical fill M₀

f. The moment that try to overturn the foundation due to resultant of vertical load as a whole and termed as R_Vmin