Infrastructure
Our Infrastructure services
Design of structure
We provide services ranging from simple structural design to prime professional with total project responsibility through construction. Projects include office buildings, schools, hospitals, and heavy industrial structures.
Services Provided:
Soil Nailing
Soil nailing technique
NSS Engineers & Geotechnical Services is please to be the consultant for execution and to design the soil nailing technique for stabilization of the natural or manmade soil slope. We have been regularly using this technique for the stabilization of the soil slope in different challenging environments with satisfactory approach. The theory of the soil nailing and its application is discussed below for observation and consideration of the facts of this technique. It is completely our pleasure to take an opportunity for implementing the applications of this technique.
The soil nailing is the technique which is use to reinforce the existing ground by increasing the normal loads (and hence the shear strength) on potential sliding surfaces through the nails, which is simply consist of steel tendon, but most commonly the tendon is encapsulated in a cement grouted body to provide corrosion and improved load transfer to the ground.
It is an effective an economical method to stabilize the excavated soil face or landslide zone. Soil nail technology was first used in France to build a permanent retaining wall cut in soft rock, whereas the first soil nail wall to use modern soil nailing techniques was built near Versailles in 1972. After that it has been common methodology for the stabilization of the soil mass in different applications. Destabilization of the soil mass caused by the increase in tensile force compare to the compressive force or normal force (resisting force). In this technique nails work predominantly in tension but are considered by some work also in bending/shear in certain circumstances. The effect of the nail reinforcement is to improve stability by a) increasing the normal force and hence the soil shear resistance along potential slip surfaces in frictional soils and b) reducing the driving force along potential slip surfaces in both frictional and cohesive soils. A construction facing is also usually required and is typically shotcrete reinforced by welded wire mesh. In soil nailing, the reinforcement is installed horizontally or sub – horizontally, which would be approximately parallel to the direction of major tensile straining in the soil to minimize the tensile force and to maximize the resisting potential of the soil mass through nail-ground interactions.
Best suited conditions for soil nailing
Design of soil nailing
Design of soil nailing for stabilization of respective soil mass
could be executed with two approaches i.e. the selection of limit
states and design approaches. Again there are two common limits
has to be considered i.e. strength limit and service limit states.
The strength limit state is the limit state that addresses
potential failure mechanisms or collapse states of the soil nail
wall system. The service limit state is the limit state that
addresses loss of service function resulting from excessive wall
deformation and is defined by restriction in stress, deformation
and facing crack width under regular service conditions.
In
design approaches the initial design considerations include wall
layout (wall height and length), soil nail vertical and horizontal
spacing, inclination of soil nail, length of soil nail and
distribution, soil nail material and relevant ground properties.
After considering these all parameters the design engineer has to
be evaluating the nail length and maximum nail force. Nail length,
diameter and spacing typically control external and internal
stability of the wall. These parameters could be adjusted during
design until all external and internal stability requirements are
met. After the initial design is completed, final design
progresses where the soil nail wall has to be tested for external
and internal failure modes, seismic considerations and aesthetic
qualities. Drainage, frost penetration and external loads such as
wind and hydrostatic forces also have to be determined and
included in the final examination of the design.
Construction of soil nail
With the design complete, the execution of the soil nailing and
the construction of soil nail wall is the next step. Most soil
nail wall construction follows a specific procedure. Its
construction process is faster than other similar methods. The
construction process start by cutting the soil face, which would
be approximately vertical and after that put the temporary bracing
at that excavated soil face, if necessary. This can be manually
performed or can be used earth moving equipment. After that start
the drilling into the soil, where the nail, steel bar, is going to
be placed. The holes for the soil nails are drilled at
predetermined locations as specified by the design engineer. The
equipment used for this step is dependent on the stability of the
material in which the soil nail is supporting. After inserting the
nails into drilled holes, it must be grouted into the soil to
create structure similar to a gravity wall.
With the holes
drilled, the next step is to install and grout the nails into
place. After all nails are inserted, a drainage system is put into
place. Synthetic drainage mat is placed vertically between the
nails heads, which are extended down to the base of the wall where
they are most commonly connected to a footing drain. A layer of
shotcrete is applied and bearing plates are installed before a
final facing is put in place to complete the soil nail wall.
Variations of the steps described above may be necessary to
accommodate additional preparation tasks or supplementary
activities for specific project conditions.
Advantage of soil nailing
Application of soil nailing
Project Management Services
Our experienced staff has diverse technical and management skills., Testing and Research Services to the Civil Engineering Profession and Geotechnical Engineering in particular. We specialise in providing Geotechnical Consultancy for Hydro Projects.
We also provide project management consultancy services which include supervision of work in accordance with technical specifications, preparation of running account bills, final bills, Interaction with the clients and contractors.
Services Provided:
Laboratory Testing
We feature in-house capabilities to provide laboratory testing of soil, rock, concrete, coarse & fine aggregates, mortar, bricks, tiles etc. We follow current BIS test procedures for tests conducted by our firm, and stay abreast of changes in methods along with new procedures through our membership in the Bureau of Indian Standards (BIS). For tests not covered by BIS, International Standards are followed. Laboratory test results are issued in concise computer generated formats and graphics with supplemental data acquisition reports available upon request. Our in-house laboratory testing capabilities are summarized as follows:
SOIL:-
Intact Rock & Rock Joints
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Intact Rock |
Rock Joints |
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CONCRETE TECHNOLOGY
COARSE AGGREGATE
FINE AGGREGATE
MIXING & CURING WATER
FILTER MATERIAL
STEEL REINFORCEMENT
BRICKS
Tiles
Geotechnical Engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. Geotechnical engineering includes investigating existing subsurface conditions and materials; assessing risks posed by site conditions; designing earthworks and structure foundations; and monitoring site conditions, earthwork and foundation construction.
Construction project reviews have consistently shown a major factor in delay and cost overrun to be the unforeseen conditions in the ground. The provision of solutions requires a thorough understanding of soil, rock and groundwater interactions.
Cost-effective site investigation, combined with experienced interpretation of the data collected, is an essential element of project risk assessment and management.
We provide complete feasibility assessment, design and project management service in all aspects of ground engineering, we are able to combine knowledge with experience to provide cost effective solutions.
We provide the following Field Testing Services:- SOIL INVESTIGATION:
ROCK MASS CHARACTERIZATION:
CONCRETE TECHNOLOGY AND CONSTRUCTION MATERIALS:-
Concrete Technology is a vital technical input relevant to any large civil engineering concrete construction project. NSS pay personnel are experts of national repute in the fields of structural engineering, concrete technology & Construction materials. Some of the prominent activities are listed below:
NSS laboratory personnel are having more than a decode of experience in evaluation of construction materials, design of concrete & mortar mixes, laboratory & setting up of laboratories, specialized tests on concrete etc.
Geological Investigation
Geological investigation is a very much important part in civil engineering as well as in infrastructure development. With an ever increasing demand for housing and development of infrastructure, the surface and subsurface geological condition has widely been considered as an important parameter. NSS Engineers & Geotechnical Services takes an opportunity to perform all types of geological investigations using advanced and highly recommended tools.
The list of Geological investigations are given below –
Geophysical Survey
The application of Geophysics to challenging geologic, environmental, engineering, or other scientific problems provides an alternative, often unique, insight into the subsurface unlike more conventional assessment methods such as drilling. NSS offers its clients site investigation strategies that reduce the likelihood of overlooking unexpected subsurface conditions while enhancing the understanding of subsurface site characteristics. The expertise of the NSS Geophysical professionals makes it possible to provide our clients with high quality services to address a wide spectrum of needs and situations. Geophysics can enhance investigation of an enormous range of projects including such diverse examples as dams and underground powerhouses, storage tanks, environmental site assessments, determining depth to rock and mapping subsurface features in geotechnical investigations, fracture and aquifer mapping in hydro geologic investigations, providing detailed stratigraphic data in coal exploration, and locating burials and artifacts in archaeological studies. NSS offers a diversity of surface and borehole geophysical methodologies. With the rapid growth of information and digital technologies, high quality, routine, and cost-effective applications of sophisticated geophysical methods have become possible. NSS has dedicated itself to being a leader in effectively delivering geophysical services in this rapidly evolving, high-tech field. NSS is committed to providing its clients with high quality geophysical surveys and professional reports written in a manner that emphasizes NSS's understanding of each client's chief concerns.
Services Offered Include:
GPR Investigations
Slope Stabilization
Slope stabilization poses some of the most complicated design and construction challenges in our industry. Our knowledge of geological conditions and sensitivity to the environment allows us to specialize in difficult stabilization installations, such as unpredictable excavation support, unusual terrain, and infrastructure interference in either rural or urban settings.
In addition to quick response to our clients’ needs, NSS offers technical skill in design & and construction covering:
SLOPE STABILIZATION:-
GROUND IMPROVEMENT:-
(A)Cohesion less Soils:
(B)Soft Clays
(C)Expansive Soils:
Dispersive Soils:
Our Services
Topographic surveying involves the production of maps and plans, which are true to scale. Topographic maps are produced to accurately represent details of both the natural and built environment. They will also include symbols representing features or data too small to produce to scale.
Our Survey team regularly carries out high standard site surveys for our clients. Topographical and Site Surveys are directed towards planning and design for engineering purposes.
We provide services for small and large scale topographical surveys customized to the clients’ needs.
Areas Covered:
Pile Testing
NSS provides site pile testing and pile condition reporting services to the construction industry. These services include Pile Integrity Testing (PIT); Cross Hole Sonic Logging; Pile Length Measuring and consultancy on the capacity and serviceability of piles. We use the latest site testing equipment and analysis software to provide a fast, efficient and cost effective service.
Pile Integrity Testing (PIT)
Defects in concrete piles caused either during or after construction may seriously affect their performance in service. Load testing of piles may be used to check the assumptions adopted in the load capacity design of the piles. However, it is too expensive and time consuming to use load testing as a means of checking workmanship. Modern non-destructive methods based on small strain impulse techniques enable the integrity of all the piles on a site to be established rapidly and economically to enhance confidence in the foundation. The test is performed using a portable, battery powered unit which requires no backup vehicle or vulnerable cables across site that disrupt normal construction activity. The test equipment is based upon the most modern digital data acquisition and signal processing techniques currently available, thus maximising the resolution and effectiveness of the test system. In excess of two hundred piles per day may be tested with this unit, depending on access and pile head condition.
Cross Hole Sonic Logging (CHSL)
The CROSS-HOLE SONIC LOGGER is used to detect defects in concrete structures and in other solid structures such as rock or concrete-rock interfaces. Defects that may be detected using sonic logging include: honeycombing; segregation due to improper concrete placement methods; washout of cement due to groundwater flow; cracks in pile shafts due to shrinkage; inclusion of foreign material causing contamination of concrete; necking and arching of piles due to collapse of side walls during withdrawal of temporary liners.
Vibration Monitoring & analysis of vibrations for optimisation of hammer parameters for compaction of soils, at power house sites due to turbo-generators, during driving of sheet piles, due to traffic in rock mass , in abutments due to movement of overhead trolleys & for assessing safety of constructed due to vibrations imposed by blasting etc.
Repair and Rehabilitation
Structural Repair Strategies:
Our core capabilities include the identification and design of thoroughly-formulated structural repair strategies for building facades, high-rise commercial office buildings, public buildings, high-rise residential buildings, industrial plants, civil structures, masonry and concrete dams, bridges fire-affected structures etc. We also undertake recommendation of restoration & repairs measure of Heritage buildings and structures Our work includes concrete, brick/stone masonry & steel structures. We also solve building roof waterproofing problems through the use of various types of roof membrane systems.
Use of Latest Concrete Repair Materials and Equipment:
NSS has access to the latest technology in both concrete repair and related materials and the necessary equipment, enabling us to solve clients' maintenance and repair problems through integrated solutions tailored to the short, immediate or long term measures as appropriate
NSS is dedicated to creating value for its asset management customers by utilising best practices, methods and technology to solve structural repair and restoration problems being forced by owners and managers
