General Safety Guideline for Operation of Concrete Pump

Familiarization of pump & booms used in concrete work is very important prior to operation of pump without any supervision. Now what is safe operation of concrete pump?

Safe operation includes:

•  Inspection of pump before leaving equipment yard,

•  Driving safely to jobsite
•  Operation of concrete pump safely after setting up in the jobsite
•  Clean up of pump and driving it back safely to yard or drive to other pumping job.

Personal protective equipment:

Before entering jobsite, pump operator should have personal protective equipment stated below:

• Safety helmet

• Comfortable work cloth

• Safety glasses or goggles

• Gloves

• Heavy duty shoes

• Rubber gloves and boots (while cleaning)

• Breathing mask (when there have possibility of exposed to any types of dust).

It is important to ensure availability of all required tools related to pumping. Sometimes personal protective equipment are required like

• Hearing protection

• Steel-toe shoes

• Shirt having long sleeves

Before staring of engine, operator should check

• Engine oil

• Hydraulic oil

• Radiator water

• Yell of engine

All safety covers, grates, gauges, tires, outriggers should be inspected for proper operational safety. Appropriate clean out equipment for particular site should be ensure and pump operator should check adequate safety slings, chains or cables are available for particular system that may drop or fall.

Safety sling should be anchored to boom but not to pipeline. All clamps when required must be pinned including boom. The operator should go through operation manual of manufacture before operating any pumping equipment and if not understand any term or procedure, should contact with manufacturer. Only one selected person can guide pump operate for moving boom and should be predefined. The hand signals (14 safety signal), used in safety regulation should be learnt by all pump operators. The job site should be kept free of alcohol and drug.

Sometimes electrical wires may obstruct free movement of boom and American Concrete Pumping Association recommended to ensure a position of spotter who will be a dedicated person to guide operator to avoid accident. When voltage of electrical wires exceeds 350 kv and electrical wire is within 50 ft of concrete poring area, the spotter is essential.

When voltage is ≤350 kv the distance reduced to 20 ft. The spotter monitors boom movement and warn operator about possible accident. No amendment is valid for this rule form local, state or other requirement of national law.

It is expected to work on clean job area and should be kept clean. Never go into valve or water box; this will prevent serious injury. The water box should be kept covered while machine is in operation (ensure cover of box to remain in place). When the cover has to be removed, transmission should be cut off and accumulator bled should have zero pressure.

A professional concrete pump operator should have following qualification:

• Good driver-knowledge of pump operation

• Mechanically sound

• Good public relation skill

• Good judgment on safe operation of pump.

Why are Index Properties of Soil Required in Addition to Engineering Properties?

Engineering properties of soil that are frequently used in geotechnical engineering are:

a. Permeability

b. Compressibility

c. Shear strength

Permeability:

This is the property of soil that facilitates water to flow through them. The main importance of this property is to measure seepage discharge (either water or soil particles with it) throughout earth masses.

ConMatic IPC, automated soil consolidation system

Compressibility:

This is the property of soil which defines deformation of soil mass under compressive loads. This property is required to estimate settlement of foundation on soil.

Shear strength:

Shear strength defines capability of soil mass to counteract shear stress. This property helps us to determine following capabilities of soil

• Slope stability

• Bearing capacity

• Pressure on earth retaining structures.

Now what are index properties? –these are properties that are not determined in geotechnical engineering for primary purposes of foundation design and analysis but helps engineers to have idea about engineering properties.

The major index properties for coarse grained soils are

• Particle size

• Relative density

The major index properties for fine grained soil are consistency or atterberg’s limits.

Now we have defined engineering properties and index properties; why should we go for index properties? Engineering properties are the main properties with which (using one or more) we can design a foundation. Say with shear strength we can determine bearing capacity of foundation soil and with compressibility we can determine settlement criteria for loosely compacted cohesionless soil or time consuming consolidation of cohesive soils. 

The consolidation tests required several days, again shear strength test required sophisticated instrument for both testing and collecting sample (undisturbed) from field. So engineering properties determination tests are laborious, time consuming and elaborate. Geotechnical engineers are often interested on index properties to gather rough knowledge about engineering properties. The simple tests that are conducted in lab or field (index properties) are called classification tests.

Here soil is indentified based on classification and often index properties offer good prediction of engineering properties. Even methods of testing engineering properties are also selected based on index properties; say draining and confining conditions during shear strength tests.

Soils having identical index properties are often found /assumed to have same engineering properties. But the correlations between two sets of properties are not perfect and reasonable factor safety should be employed if index properties are the basis of design. It is not recommended to design important and large structure only depending on index properties.

Requirements of Sheath for Micropile Encapsulation

We know sheath is used for encapsulation purposes; the encapsulation is required for aggressive exposure of micropile, especially when subjected to tension loading.

Sheath is essential part of corrosion protection process for unbounded length, later we will discuss about encapsulation of bond length. Sheath may be smooth or corrugated.

Smooth sheath can also be used as bond breaker as discussed in last post. When sleeves are used that may shrink with temperature change or sheaths of corrugated tube are used, separated bond breaker has to be used. We have discussed about requirements of bond breaker in last post.

Sheaths fabricated by following materials were found to have satisfactory performance:

• A tube made of hot-melted extruded polyethylene comply ASTM D1248,Type III


• A tube made of hot-melted extruded polyethylene comply PP210B55542-II,as per ASTM D4101


•  A corrugated tube satisfy requirements of encapsulation of bond length

These are the specifications according to which sheathing material is selected. The required properties for sheathing material are as following:

• Should have resistance against chemical attack; the aggressive environment, corrosion inhibition or grout are considered to produce chemical attack.

• Should have resistance against aging from UV-light

• Not harmful to any type of reinforcement

• Should have ability to withstand

 Impact 

 Abrasion

 Bending while handling & installation

• Allow reinforcement enclosed by sheathing to elongate under stressing and testing.