2001 ACI Award

Tecvac, Inc. Receives

Award of Excellence

For Concrete Repair

ecvac, Inc. is the proud

recipient of the National

Capitol Chapter of The

American Concrete

Institute's Year 2001 Award of

Excellence in Concrete Repair for

work it performed at the Historic

Union Station in Washington, DC.

For the second year in a row,

Tecvac has been recognized by its

peers for completing a difficult

project using its exclusive vacuum

processes.

Using its proprietary TecSealtm

Process of leak repair, technicians

successfully mitigated a host of

chronic leaks in the station.

Technicians also performed

structural repairs without surface

destruction or marring of the historic

members.

Tecvac, Inc. is an internationally

recognized leader in innovative

repair techniques for concrete,

masonry and stone using vacuum

technologies. Call today for more

information.

Tecvac, Inc. 39482 Rickard Road

Lovettsville, VA 20180

Office 703 742-9186 FAX 703 742-9231 toll free 800 847-9324 www.tecvacinc.net

For the Second Year In A Row, Tecvac, Inc. Has Been Presented With the

NCC/ACI's Award of Excellence For Concrete Repair

T

K

Chronic Leak Mitigation

Washington Union Station

Washington, DC

Tecvac, Inc.

39482 Rickard Road

Lovettsville, VA 20180

800 847-9324

Union Station Link Ramp Structure 1

Mitigation of Water Intrusion


General Description

This project began as a difficult leak repair job. It quickly evolved into a

structural repair project that was merely complicated by water intrusion.

Each time a new area or joint was opened up, it was anyone's guess what

condition the underlying members would be found. On more than one occasion it was

necessary to install emergency shoring because of the extensive deterioration of concrete

discovered. As it turned out, beams and columns were rebuilt, structural steel supports

were installed and prestressed cables were repaired. In one instance, a hole area of ramp

was removed, the cable ends repositioned and the area converted to beam and slab.

After years of leakage, one column was found to be mostly aggregate. The matrix

was so deteriorated that it could be dug into with a pocket knife for several inches.

Because of its position within the Link Ramp, replacement of the column would have

caused long term shut down and long term disruption of ongoing tourist operations. The

contractor used a unique vacuum method where the column was bagged and impregnated

with acrylic repair resin. Total restoration was completed in just two days with no

disruption to operations.

The expansion joints also posed a difficult task of replacement. No less than five

previous attempts by others failed to install a lasting joint. Sometimes within weeks, the

newly installed joints were failed and leaking. The Contractor in this project used a

combination of innovative techniques and materials that have now been in place for

almost two years with no signs of deterioration or leakage.


Mitigation of Water Intrusion


This project entailed mitigation of water intrusion into Amtrak passenger

boarding areas and other areas of occupied space at Washington Union Station. This

proved to be an intense task spanning a range of complexities. From simple concrete

removal and replacement to prestressed cable repairs, the Contractor was more notably

faced with the results of chronic leakage and contamination of a throng of concrete

members and configurations. Although not fully described, the multi-tasked operation

included extensive testing, demolition, structural concrete repairs, expansion joint

removal and replacements, prestressed cable repairs, waterproofing, bearing pad

replacements, emergency shoring, structural steel fabrication and drain installations.

Modeled after the public baths of Diocletian in Imperial Rome, Union Station was

opened to the public in 1907. Departing passengers in the first decades would have

entered the majestic structure from the Western Carriage Porch. Upon entry into the

Main Hall, it is very easy to imagine the bustling throng of travelers from times past.

The Roman Legionnaires still stand behind their shields on the balconies at the

mezzanine level, guarding the tourist and travelers below. Changes have been made over

the years but a chronic problem has existed since construction; water intrusion.

Sometimes it was in the shadows and sometimes it was an open embarrassment.

The proud and imposing structure has been in a constant state of improvement

and repair. While there are reams of history, including war-time take over during WWII

and a horrific crashing of a runaway locomotive in 1953, this water mitigation project


was of times that are more recent. It is interesting to note however, that when

diminishing rail travel threatened demolition in 1964, the roof had been repaired and

completely replaced a number of times. The station was granted landmark status under

the Historic Sites Act of 1964 and listed on the National Register of Historic Places in

1969.

In 1968, Congress designated Union Station as the site of the National Visitors

Center. The Center was to be operated by the National Park Service. It was at this time

the railroad owners agreed to renovate the main hall for tourist functions and to construct

a parking garage. The garage would adjoin the North face of the station and would

accommodate 4,000 cars and 100 buses. In exchange for the renovation and construction,

the Department of Interior agreed to lease the station for twenty-five years.

In 1973-74, the AMTRAK Improvement Act was passed where Congress

authorized federal funds to supplement development of the Visitors Center. With less

than half of the parking garage completed, and cost overruns approaching $5 million, the

construction work was forced to halt. The Department of the Interior opened an

truncated version of the Visitor Area in 1976, but without parking facilities it was little

visited. By 1978, Visitor Center functions were further curtailed when federal

appropriations were reduced. The whole Visitor Center issue was mired in Congressional

controversy and the uncompleted work at the Station continued to deteriorate until

Congress passed the Union Station Redevelopment Act in 1981. This Act stabilized

funding of the project and, despite numerous disputes and delays, ultimately positioned

dedicated individuals who would transform the Station into the magnificent and complex

structure we visit and travel from today.


The parking garage was finished by the District of Columbia Department of

Public Works with Sverdrup and Parcel serving as Architects. While a number of pages

could be written regarding the controversies surrounding its construction, let it suffice to

say that the transitions necessary to make the garage an intregal part of the station was a

formidable task under the best circumstances. Consequently, the melding of the Garage

to the Station has been the curse of maintenance and cleanup crews from the beginning.

When this contractor began its work in late 1999, attempt after attempt had

already been made to resolve the water intrusion along the Garage/Station junction line,

known as the Link Ramp Structure. In the previous seven years, diligent attention was

devoted to the water intrusion problem; studies were conducted, testing was performed

and repairs were made. Yet, all efforts proved to be unsuccessful and the water

continued to flow into the occupied space below. Often, AMTRAK passenger waiting

areas were blocked off, passageways were maneuvered around large trash cans used to

catch the water and often, the Metro Station located three levels below would move desks

and office equipment to avoid the incoming water.

After examining the site, reading all the reports and inspecting the previous repair

attempts, the Contractor positively identified no less than twenty conditions possibly

contributing to the leakage. It was found that some of the leaks were easily mitigated,

while others were complicated travels requiring resolutions that were more extensive.

One of the leaks, known for decades to be a "sometimes it does…sometimes it

doesn't" sort of leak was tracked to the louver of a rooftop air handling unit adjacent to

the Ramp Link Structure. In an effort to once and for all take care of the leak, the Owner


had replaced the entire roof and required that all copings and flashings were to be solder

sealed. Still, the water continued to leak into the passenger waiting area…sometimes.

Although believed to be outside the Link Ramp Area, the Contractor thoroughly

inspected the previously installed roofing system and could find no deficiencies or source

for the intrusion. While the base legs of the air handling unit were closely inspected and

found to be watertight, it was concluded that the source of the leak was positively in the

same location below. Water testing confirmed that rain water flowed from the top of the

unit onto the top louver of the exhaust vents. The louver was mounted with a slight angle

up. As heavier rains filled up the louver, the water would freely overflow the end of the

louver and into the building. Other leaks were not so simple.

The host of possible conditions were ultimately whittled to three primary causes

that included deficient expansion joints, unsealed construction joints and deficient surface

drainage. More importantly, the contractor's inspections also revealed serious structural

problems caused from the chronic leakage. In some instances, where the expansion joints

leaked, the repeated wet/dry deterioration had severely compromised the structural

integrity of the prestressed slabs and beams, and the columns below. This condition

prompted immediate support shoring and reconstruction of the members in a number of

locations.

Another mysterious source of the leakage was found to be a concealed

construction joint located under a sidewalk area that extended 250-300 lineal feet along

the Ramp. When the sidewalk was removed, the whole length of the joint was found to

be open and free flowing into the space below. A gutter system had been attached years


before to the wall in some areas just below the joint, apparently to divert the flow at some

of the leakage spots.

The joint line was thoroughly cleaned and repaired with polymer modified

patching material. A liquid waterproofing material was vacuum injected into the joint

line and the entire length was covered with an embedded elastomeric waterproofing

membrane before the sidewalk concrete was replaced.

As noted above, the transverse expansion joints located in the Ramp were in a

continual state of disrepair. Despite numerous replacements, it appeared that no joint

could withstand the onslaught of extreme bus traffic and the non-stop automobile and taxi

traffic that utilized access to the garage and station. Many brands and types of joints

were installed, promising long term wear and protection only to find disappointment

within months. Sometimes, within mere weeks the newly installed joints were "flopping"

under traffic and then leaking into the AMTRAK passenger waiting areas during

inclement weather.

The Contractor chose to install a joint manufactured by the D.S. Brown Company.

It was understandable that maintenance and clean up crews were pessimistic when the

Contractor began its work on the joints above. There was even some confidence

expressed (in the form of wagers) that the Contractor's promise would soon be replaced

with the large trashcans used to catch the water.

The deficient joints were removed and the slab edges on either side were repaired

and shaped. The length of the joint was saw cut some twelve inches away and the

concrete was removed to a depth of about two inches. The modification continued across

the joint and up the parapet wall on one end and column on the other. The newly


exposed surface was vacuum impregnated with acrylic repair resin and the studded steel

extrusion was embedded into the depressed area. The extrusion was embedded with a

specially formulated polyurethane material mixed with graded aggregates and fibers.

When the nosing material was fully cured, the expansion gland was installed. It is

important to note the gland was continuous single piece and contained no welds.

The water mitigation and joint replacements are now well into the second year

with no sign of disrepair or leakage into the station below.

West Ramp of Union Station Link Ramp


Looking West on Link Ramp

Water Testing Construction Joint Under Sidewalk


Removing Concrete To Reveal Joint

Water Discovered In Revealed Joint


Existing Joint Assembly Before Removal

New Joint Extrusion Installation


New Polyurethane Nosing Material Installation

Installed Joint Assembly


Severe Condition Revealed Under Sidewalk

Deterioration Damage To Structural Concrete Members Below


Damage To Interior Finishes

Testing Load On Prestressed Cables


Total Column Removal

and Replacement

Documents

2001 ACI Award