Car parks are a blight on the landscape

of a town center. Their empty concrete

automotive housing efforts always make

me think of the massive space waste they

create. However, as a person who has a

car, I'm very much aware that they are a

necessary evil in order to avoid some of

the more awkward to reach places by

public transport. If it weren't for car

parks, I would never get to enjoy such

magical places as the aisle of Shepy

Strude and the beautiful Red Hill. One

such place that I haven't been to, but

it's often slated as one of the most

beautiful English towns is Wolverampton,

but I joke. Regardless, today's video is

about a subject that is a rather staple

on this channel. This is of a structure

deciding being in one piece was all

rather too much bother and promptly

unassembling itself in a catastrophic

fashion. Today's video is about the

Piper Row car park collapse. My name is

John and welcome to Plainly Difficult.

This video wouldn't have been possible

if it wasn't for my YouTube patron and

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links will be in the pin comment below.

Piper's Row. So, our story starts back

in the 1960s with the construction of a

new car park in the sunny and up market

city of Hampton. The city's history is a

long one, dating back to pre985

AD. Of course, cars weren't much of a

thing back in old ei time. So, we're

really going to be focusing more on the

1960s. So, this new car park was to be

built using a kind of controversial

method of construction, the lift slab

technique. This method is beneficial for

speed and cost in building buildings. It

allows for concrete to be manufactured

before installation. It was originally

developed in America, but became very

popular in the UK during the let's make

everything in a town center out of

concrete era, aka the 1960s. Hence why

many English towns look so bleak in the

center. Just look at the beautiful

architecture of Cudden. So the method of

building runs as follows. First,

builders construct foundational blocks

with sockets for pre-cast columns to be

installed.

Then the columns are installed with

wedge seings at each level that the

floors will be installed upon. Next, the

large sections of the reinforced

concrete floor slabs are cast at ground

level, one on top of each other. Bond

breakers are used in between each slab

for separation during the lift. Once all

the floors are ready and the concrete is

set, the slabs are lifted up the columns

via hydraulic jacks to level of the

seings and setting them on the four

wedges. Once at the correct height and

seating builders then infill with mortar

between the shear head and the column to

create a moment connection between the

column and slab. Then casting is done on

the infill sections between the large

sections of floor slabs to join up the

whole structure. It's ideal for building

things like car parks as it's quick and

cheap. And you know, if it's a car park,

it doesn't really need to be

particularly pretty if you're just going

to be parking your old Fort Contina for

the day of retail delights that

Wolverampton offers. The car park

lifting began during May and June 1965,

opening up to the public sometime later

on in the same year, adding 400 spaces

of car parking magic to the city. Now,

the car park would be a useful structure

for some 25 or so years until the late

1980s when repair works would be needed

with deterioration to the concrete at

the bottom of the ramp requiring a

substantial repair in 1987.

Multiple reports would come in to the

car park's owner, NCP, of general

deterioration of the car park, which

would be patched up and repaired over

the years. Leaking was a common issue

with the car park. NCP decided to bite

the bullet in 1996 and commissioned car

deck maintenance to stop leakage, patch

up some areas on the top floor and

rewaterproof the structure. And around

the same time, Harris and

Southerntherland structural engineers

inspected the structure. However, no

deep investigation of any deterioration,

assessment of the structural effects of

any deterioration or repair or

specification for a structural repair

was undertaken. Some parts of concrete

were found to be crumbling, exposing

reinforcement bars within the concrete.

The deterioration wasn't cross

referenced with design drawings. Some

parts were repaired, but others were

just left to crumble away. In January

1997,

the top deck slab was checked by CDM

again due to further leakage. During

this time, a large crack adjacent to one

of the columns was found and deemed

serious. In February of 1997, propping

around the column was considered and

planned to be installed, but was not

started. Instead, the area was coned off

as well as the floor below. The building

was not in a great condition, but oh

well. It's not like anything bad would

happen. The disaster. Ah, yeah. I knew

this would be the next section of the

video. It is the early hours of the 20th

of March, 1997, and all is quiet across

the city. Maybe apart from the odd fox

scream and the occasional taxi trenling

around. It is a cool night with the air

temperature of around 10° C.

The Pipers Row car park is pretty much

empty with the top two levels having

been cordoned off.

which resulted in no people or cars

being in the top levels at all. The

relative quiet of the early hours would

be destroyed by at roughly 20 minutes

past 3 in the morning, a catastrophic

and sudden collapse of the top floor of

the car park. The floor crashed into the

lower concrete slab

roughly 15 by 15 m in size. This slab

weighed around 120 tons. Upon crashing

down into the fall below, a progressive

collapse ensued. Some of the columns

also tipped over during the collapse.

Due to the time of day, luckily, no one

was inside the car park, and thankfully,

no one was injured or killed in the

collapse, which means it's time to smash

that button. Anyh who, the car park was

completely and absolutely ruined

requiring a total demolition which would

cause traffic nightmares for the city

which interestingly was already in the

throws of traffic disruption due to the

West Midlands Metro being built. A new

car park would eventually be built on

the site and cars would once again be

able to have a little rest as their

owners went to Wolfs or something for

shopping. But what was the cause? Well,

NCP would dig into this and also call in

the big boys. And in our case today, it

is long-term friends of the channel, the

health and safety executive.

The investigation

investigators from the HSSE arrived on

site on the 25th of March and

immediately set to work taking

photographs and samples of the wreckage.

Access to the third floor slab was not

allowed as it was uncertain if it too

would collapse under the weight of the

two slabs crashed into it. Instead, a

hoist was employed to access for imaging

the upper levels. A quite large section

was seen to have fractured and

collapsed, revealing reinforcement bars

and crumbled concrete. Samples of the

concrete was taken off site and stored

at Birmingham for further laboratory

testing. This in addition to the site

inspections pointed towards the failure

point. Let's have a look at this photo.

Can you see something concerning here?

Well, the column here looks pretty much

intact with a section of floor slab

still attached to it, but the

surrounding sections have unattached

themselves. This is called a punching

shear failure where a concentrated

section of the structure, in our case

the column, has quite literally punched

through the slab. The sections that have

remained attached to the column was

repaired areas from the year before. The

old worn out concrete had just separated

from the fresh repair works. Imagine it

like a pencil trying to support a piece

of paper. With enough force, the pencil

would just spear itself through the

paper. And this is what happened in our

building here. It was found to not have

the best puncturing sheer reinforcement

with what little it did have being

positioned incorrectly, making them

relatively ineffective.

It was found that moisture had made its

way into the structure via poor and

degrading waterproofing materials, which

had allowed frost damage on some of the

less well-built parts of the building.

The quality of the concrete was

criticized as it had deteriorated but

not the method of construction as noted

in the HSSE report. Deterioration of the

concrete over and around the column slab

zone led to the failure of the concrete

slab. The mechanical column slab

connection unique to the lift slab

method of construction did not fail. It

would seem the building was a mixture of

poorly used concrete and poor building

maintenance. If you've ever been inside

an NCP car park, you may understand.

Now, I know not all are like this, but

at least some of the ones I've been to

are rather groy and have not been the

best maintained.

It would seem the building was a mixture

of poorly used concrete and poor

building maintenance,

failing after years of basic neglect.

But at least no one died. And that's my

video on the Piper Road car park

collapse. It's going to be one on my

scale. And this what I've got for my

root cause and assist card. Do you

agree? Let me know in the comments

below. This is plentiful production. All

videos on the channel creative comuation

share like licensed pliff videos are

produced by me John in a currently quite

moderate corner of southern UK. And all

I have to say is thank you very much for

watching and Mr. Music play us out

please.