INSTRUMENTATION IN CIVIL ENGINEERING Various Instruments used in: construction Environmental Engineering Foundation Engineering STRAIN GAUGES MANAGEMENT UTILITIES USING TELEMETRY SCADA SYSTEM

INSTRUMENTS USED IN CONSTRUCTION COMPACTING EQUIPMENTS EXCAVATING EQUIPMENTS NON DESTRUCTIVE TESTING

COMPACTING EQUIPMENTS What is compaction? A simple ground improvement technique, where the soil is densified through external compactive effort. Compactive effort =

Compaction Objectives: Many types of earth construction, such as dams, retaining walls, highways, and airport, require compaction of soil, or fill. The dense state is achieved through the reduction of the air voids in the soil, with little or no reduction in the water content. This process must not be confused with consolidation, in which water is squeezed out under the action of a continuous static load. Objectives: Decrease future settlements Increase shear strength Decrease permeability

GENERAL COMPACTION METHODS Coarse-grained soils Fine-grained soils Falling weight and hammers Kneading compactors Static loading and press Vibrating hammer (BS) Laboratory Hand-operated vibration plates Motorized vibratory rollers Rubber-tired equipment Free-falling weight; dynamic compaction (low frequency vibration, 4~10 Hz) Hand-operated tampers Sheepsfoot rollers Rubber-tired rollers Field Vibration Kneading

Lab Compaction Equipments Standard Proctor test equipment

Field Compaction Equipments Vibrating Plates for compacting very small areas effective for granular soils

Field Compaction Equipments Smooth-wheel roller (drum) 100% coverage under the wheel Contact pressure up to 380 kPa Can be used on all soil types except for rocky soils. Compactive effort: static weight The most common use of large smooth wheel rollers is for proof-rolling subgrades and compacting asphalt pavement.

Field Compaction Equipments Pneumatic (or rubber-tired) roller 80% coverage under the wheel Contact pressure up to 700 kPa Can be used for both granular and fine-grained soils. Compactive effort:static weight. Can be used for highway fills or earth dam construction.

Field Compaction Equipments Sheeps foot rollers Has many round or rectangular shaped protrusions or “feet” attached to a steel drum 8% ~ 12 % coverage Contact pressure is from 1400 to 7000 kPa It is best suited for clayed soils. Compactive effort: static weight and kneading.

Field Compaction Equipments Tamping foot roller About 40% coverage Contact pressure is from 1400 to 8400 kPa It is best for compacting fine-grained soils (silt and clay). Compactive effort: static weight and kneading.

Field Compaction Equipments Mesh (or grid pattern) roller 50% coverage Contact pressure is from 1400 to 6200 kPa It is ideally suited for compacting rocky soils, gravels, and sands. With high towing speed, the material is vibrated, crushed, and impacted. Compactive effort: static weight and vibration.

Field Compaction Equipments Vibrating drum on smooth-wheel roller Vertical vibrator attached to smooth wheel rollers. The best explanation of why roller vibration causes densification of granular soils is that particle rearrangement occurs due to cyclic deformation of the soil produced by the oscillations of the roller. Compactive effort: static weight and vibration. Suitable for granular soils

Dynamic Compaction - pounding the ground by a heavy weight Suitable for granular soils, land fills and terrain with sink holes. solution cavities in limestone Pounder (Tamper) Pounder (Tamper) Mass = 5-30 tonnes Drop = 10-30 m Crater created by the impact (to be backfilled)

Vibroflotation Vibroflotation is a technique for in situ densification of thick layers of loose granular soil deposits. It was developed in Germany in the 1930s.

Vibroflotation Suitable for granular soils Vibroflot (vibrating unit) Length = 2 – 3 m Diameter = 0.3 – 0.5 m Mass = 2 tonnes (lowered into the ground and vibrated)

EXCAVATING EQUIPMENTS An excavator is a power-driven machine mostly used in earthmoving operations.

EXCAVATING EQUIPMENTS Backhoes: Backhoes are used for surface or subsurface excavation of solids and sludge. Backhoes are used to dig below the surface, such as trenches, building footings and foundations. The backhoe is attached to the loader frame with a ridged coupling. Excavators: Excavators are large backhoes. They can be truck mounted, truck carrier mounted, or self-propelled wheel mounted. They are hydraulic powered and consist of three structures: the revolving unit, the travel base and the attachment.

EXCAVATING EQUIPMENTS Front-End Loaders: The front end loader is a self-contained unit mounted on rubber tires or tracks and is one of the most versatile and capable pieces of equipment used in excavation work., as well as loading. The front end loader can be equipped to operate as a loader, dozer, scraper, backhoe, crane, auger, or sweeper.

EXCAVATING EQUIPMENTS DOZER: A bulldozer is a crawler equipped with a substantial metal plate (known as a blade) used to push large quantities of soil, sand, rubble, or other such material during construction or conversion work and typically equipped at the rear with a claw-like device (known as a ripper) to loosen densely-compacted materials.

NON DESTRUCTIVE TESTING EQUIPMENTS Non Destructive testing of buildings means analyzing the condition of building after construction or of an existing construction. Usually used for old buildings for the repair and maintenance work.

NDT Advantages Access to hidden items – “see through walls” Better investigations with NDT Rapid accumulation of data Generally less expensive than destructive testing Minimize interruption of building services Evaluation and quality assurance

NDT Disadvantages More than one test method may be required Environmental conditions may effect or distort results Construction details & building components may effect results Some conditions cannot be determined with a reasonable degree of accuracy without destructive testing

Non Destructive Testing Methods Schmidt rebound hammer test Ultrasonic pulse velocity test Carbonation depth measurement test Permeability test Penetration resistance or windsor probe test Infrared thermography

NON DESTRUCTIVE TESTING EQUIPMENTS SCHMIDT REBOUND HAMMER Utilizes an internal spring and rod to strike the concrete with a calibrated force Weight – 1.8 kg Can be used in lab and field Easy to use Variable results

NON DESTRUCTIVE TESTING EQUIPMENTS DIGI-SCHMIDT Digital Concrete Test Hammer • Non-destructive measurement of the concrete/mortar compressive strength • The control of the uniform concrete quality (in-situ concrete and prefabricated structures) • Detecting weak spots • Electronic display unit makes it ideally suited for systematic high volume measuring. The compressive strength (fc) is established by measuring the hardness (rebound value R) of the concrete surface and with the conversion curves. Measuring range: Concrete compressive strength of 10 to 70 N/mm2.

NON DESTRUCTIVE TESTING EQUIPMENTS ULTRASONIC PULSE VELOCITY TEST Equipment consists of an electrical pulse generator, a pair of transducers, an amplifier and an electronic timing device for measuring the time interval Measure travel time of an ultrasonic pulse Correlates to compressive strength

NON DESTRUCTIVE TESTING EQUIPMENTS ULTRASONIC PULSE VELOCITY TEST APPLICATIONS:  determination of the uniformity of concrete in and between members  measurement of changes occurring with time in the properties of concrete  correlation of pulse velocity and strength as a measure of concrete quality  determination of the modulus of elasticity and dynamic Poisson's ratio of the concrete. Direct transmission Semi-direct transmission Indirect or surface transmission

NON DESTRUCTIVE TESTING EQUIPMENTS

SPECTROPHOTOMETER Principle: Light Intensity Change : By Absorbance or Transmittance Quantity : Using Absorbance Use: To determine the intensity of transmitted light To Determine the absorbance or transmittance Used in dyes industry To determine colour impurities in water

Working Principle of SPECTROPHOTOMETER It photometer spectrometer Sample Holder I0  Intensity of incident light  Intensity of transmitted light It