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October 11, 2010
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Question: One of my in-bay automatic guides on the floor has been hit so many times that it’s loose. I need to move it and drill new holes in the concrete. How far should I move the guide from the old holes? Will I need to drill all the way through the concrete for the anchors? How can I make sure the anchor seats?

Masonry anchors in the modern carwash lock the IBA track firmly to the floor, adhere signage tightly to the wall and hold transducers firmly in place. There are three basic types of masonry anchors:
  • Mechanical,
  • Powder activated; and
  • Chemical.
The mechanical anchor it is the most common in the carwash industry.

Drill technique
Mechanical masonry anchors require drilling with specific drill bits. A cheap, smooth shank masonry bit used in a regular drill will not drill as fast or as many holes as a machine grooved shank masonry bit installed in the proper hammer drill. Remember to let the drill do the work for you and refrain from pushing down.

When drilling into concrete reinforcement bar or aggregate, the bit can catch and stop. If this happens, simply pull up on the drill or reverse it if possible. If this does not work, pull up on the drill and pulsate the drill trigger.

If all else fails, remove the drill from the bit and use vice grips to back the bit out of the hole. Do not clamp the vice grips to the machined grooves of the shank. If it is impossible to remove, the bit will have to be cut off flush.

Equipment repositioning may be required if you are unable to make a new mounting hole in the equipment. If you can remove the bit and start drilling again, lower the turning bit slowly into the hole. As soon as you feel the bit starting to bite, pull up slightly to keep the bit from catching. This may have to be done several times to complete the hole without the bit sticking.

Many times, the bit cuts just enough of the rebar or aggregate to allow it to pass by without cutting a proper hole. This is how the bit becomes wedged in the hole. By lifting just as the bit bites, you can slowly cut through the reinforcement bar or aggregate without the bit catching.

Before inserting the anchor, make sure all of the drilling dust is removed from inside and around the hole. Dust removal tools usually resemble a small turkey baster, using air to blow dust from the hole and surrounding area.

Determine load
Once the dust has cleared, consider the type of load the anchor will carry. Anchors are rated for two types of loads: shear and tensile. Shear loads occur when the weight of the equipment exerts force parallel to the surface of the concrete. Tensile loads occur when the equipment exerts force perpendicular to the surface.

Many times, the equipment exerts a combination of both shear and tensile loads. A properly hung inferred heater anchored at the ceiling exerts a tensile load. An electrical control panel mounted to a wall exerts almost a purely shear load. A floor-mounted track anchor will be under a combination of both forces.

Other loads types include static, which are steady and constant, dynamic or vibrating loads that are constantly changing and impact loads that change suddenly.

Due to the wide variance of concrete quality, the standard recommendation is that the anchor you choose should be rated about four times the weight it will carry if it will bear a static load and eight times the weight if it will carry a dynamic or impact load. Each anchor type has its own application, so load factors must be considered when deciding which anchor to use.

Common mechanical masonry anchor types include: concrete sleeve anchor, concrete wedge anchor, drop-in anchor, concrete strike anchor, single and double expansion anchor, split drive anchor, metal hit anchor, machine screw anchor and lag shield anchor.

With its heavy-loading capacity and ability to handle both static and dynamic loads, the concrete sleeve anchor is one of the most commonly used carwash anchors. The concrete sleeve anchor is composed of four parts: the threaded stud, the split expansion sleeve, the nut and washer. Head types include: flat head, round head, and the acorn nut style, a commonly used hex nut. Regardless of head type, most sleeve anchors are made of either zinc plated carbon steel or 304 stainless.

Due to the harsh environment of the carwash, sleeve anchors may require replacement or readjustment after years of service. Often, an anchor must be reinstalled in the same location.

When replacing sleeve anchors in guide rails, track or bay treadles, you must first determine if the equipment was initially installed in the proper location. Many components must maintain exact positioning due to sensor locations, desired vehicle position and a variety of other factors.

When installing sleeve anchors, it is common practice to drill all the way through the floor. In most cases, drilling through the floor allows future replacement of an anchor using the same hole. A punch drives the old anchor through the floor and a new anchor is reinstalled without having to drill a new hole and relocate the equipment.

The wedge anchor, similar in appearance to the sleeve type anchor, is used for heavy-duty fastening applications where high pullout values are required. The wedge anchor is designed to work in solid concrete or grout-filled masonry and comes in a variety of plating and steel types including 303 stainless, 304 stainless and 316 stainless. Wedge anchor installation mirrors that of the sleeve anchor.

When installing the hex head style of sleeve or wedge anchor, position the nut so it is even with the top of the threaded stud. This increases the surface area for driving the anchor with a hammer and puts less stress on the threads. If set too high on the threaded stud when hammering, the nut can collapse the threads. If set too low, the hammer will peen over the thread and you will not be able to remove the nut.

When threads become damaged, the nut and threaded stud can spin in the hole, not allowing the anchor to tighten up. One solution for a spinning anchor is to apply upward pressure on the washer or equipment the washer contacts. The upward pressure sets the anchor allowing the nut to turn on the threaded stud thus tightening the anchor.

Determine anchor type
Like the sleeve and wedge anchor, the drop–in anchor is used in medium to heavy-duty applications. The drop–in anchor, a flush female anchor, requires a setting tool to drive the internal plug into the anchor, causing the anchor to expand. To completely set the anchor, the lip of the setting tool must meet the lip of the anchor. Drop-in anchors, ideal for overhead applications, require relatively shallow embedment. Drop-in anchors should be used in static load situations only.

The concrete strike anchor, used in medium to heavy-duty application, eliminates the possibility of the stud spinning in the hole.

This anchor consists of a pin, a hollow threaded stud with expansion slots at the opposite end as the pin, a nut and washer. Once the pin is set by driving the pin flush with the top of the anchor, there is no need to tighten the nut. This allows the nut and washer to be preset for the desired embedment. The strike anchor handles both static and dynamic loads.

Similarly, the single and double expansion anchors are both designed for medium to heavy-duty applications and will secure both static and dynamic loads in all types of solid masonry.

The single expansion anchor consists of a nut, a cone and a tubular shield preassembled in a single unit.

The double expansion anchor consists of the same components as the single unit with the exception of the tubular shield bound together with two spring bands. It contains a wedged shaped nut at one end and a wedged shape hollow cone at the other end. The wedged shape nut and the cone face the opposite direction so the holding strength is applied in both directions. Proper expansion requires the anchor, prior to setting to protrude slightly above the surface plane.

The split drive anchor and the metal hit anchors are used for light to medium duty static load applications in solid concrete.

Both types fasten electrical cabinets and j-boxes to walls by simply inserting the anchor through the mounting hole and hammering the pin flush to the head.

The split drive anchor is available in high strength, heat-treated alloy steel; zinc plated in either a flat or round head style. The metal hit anchor, a precision die-cast anchor, consists of a cylindrical zinc alloy body and a zinc pin expander.

To determine the proper length of a metal hit anchor, add the thickness of the material to be fastened, the minimum embedment and 1/4”.

Another light-to-medium duty anchor, the machine screw anchor, is used in block, brick or stone. Composed of two parts, a sleeve and internal cone, the machine screw anchor requires the use of a unique setting tool for its specific diameter. The machine screw anchor is highly corrosive resistant. It enables the removal or replacement of a fixture without a loss of holding value.

Used in light to medium duty application, the lag shield anchor is a single unit anchor with a series of circumferential ribs starting at the bottom and running for the major portion of its length. The internal thread is tapered and expands the external ribs against the hole as a bolt or rod is screwed into the anchor. Its unique four-way expansion assures a tight grip in the base material.

There are many choices when it comes to masonry anchor bolts. Not every manufacturer uses the same technique for installation even with like type anchors. It is important to follow each manufacture’s specific installation and safety procedures. Equipment improperly anchored will vibrate, resulting in damage. To keep costs down and equipment up, tightening should be an important part of your carwash maintenance program.

Mark Hartzer is the carwash operations manager for R.W. Mercer, the exclusive distributor of Ryko carwash equipment for the state of Michigan. Hartzer has been installingand servicing Ryko carwash systems for over 17 years. He can be reached at: or 1-866-841-3110.

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