SayJack…..

Riding a bike around Amsterdam can be daunting at first as one learns the basic road rules.  Then it becomes exhilarating.  You can get anywhere quickly without delays.

The family, ready to ride.

The basic road rules, as outsiders say, is “there are no rules”.  This is not true.  There are many clear rules regarding right-of-way and traffic signals, and bikes have protected bike lanes and directional privileges everywhere.  One of the basic rules is that you may break any rule on a bike as long as you don’t collide with someone else.  If you give the car/cyclist/motorbike time to avoid a collision, you’re OK.  If not, stop.  Whoever’s behind you better stop also. Instantly.  Anticipate everything that might happen in front of you so you can stop on a dime, or swerve onto a sidewalk, or speed through a gap.

No better way to learn about the city than by bike tour with guide Eva.

The roads that line the concentric canals are fun.  They’re paved with brick, one-way for cars but two-way for bikes, and they go up and down at the bridges.  Service vehicles can be parked in the middle of them, leaving a 1 m. gap to cruise through to the left or right.  Pedestrians wander down the middle of the roads.  Faster bikes pass on the left and the right.  Scenic canals line the way if you have time to look.

Motorbikes get to use bike lanes, which makes them one of the chief hazards for cyclists.

Amsterdam biking is akin to mountain biking.  It requires the same skills.  Instead of dodging rocks and tree roots, you dodge road hazards and bikes and walkers.  You are locked in.  You need quick power to get through a gap, then a combo braking/turning maneuver to avoid a pavement gap, a bunny hop to get up a curb, cold guts to face down a car reluctant to give way.  Time speeds along, the scenery is amazing and you arrive at your destination before you ever thought you could.  You even ride with low tire pressure for traction and cushioning.  No one wears helmets, though, except American tour groups constrained by liability insurance.

Oh yes, and watch for pedestrians!

We rented bikes after the first couple days for the duration of our stay, and even the novice bike riders among us enjoyed the freedom and challenge of two wheels.  It’s the quintessential Amsterdammer way to experience the city, although our bike helmets and timidity assured we wouldn’t be mistaken for natives.

A particularly tricky maneuver is required when a ghost wheel appears in front of your bike…..

Honderd hipsters dominate the Amsterdam bike scene.

Amsterdam features a special segment of Dutch engineering.  To build a city in a swamp, the Dutch had to figure out a way to keep buildings upright.

Wood pile driving in the early days.

Initially, they built one and two story wood buildings on cowhides.  The cowhides spread the light loads enough to keep the houses mostly afloat—an improvised raft.  This was not a long-lasting solution, both because of the limited life of wet cowhide and potential fire damage to the wood building above.  After much of Amsterdam was destroyed by fire in 1452, the ruling power declared that all new structures had to be built of brick.  This required new means to support the additional weight:  wood piles.

What’s wrong with this picture? Piles!

Until recently, most Amsterdam buildings have been built on wooden piles.  Amsterdam’s water table hovers about 1 m. below the surface, rising or falling with rain and drought.  The nearest layer of bearing soil is a stria of sand 12 m. below.  To reach this, Amsterdammers drove wood poles—generally pine or spruce—through peat and marl.  The Centraal Train Station, for example, was built in the late 1800’s using over 8,000 wood piles.  As long as the piles stay wet continuously, they do not rot.  If the tops of piles extends above the water table and are subject to wet/dry cycles, however, they will eventually rot, causing a difficult structural problem.

The crack can be patched but will the floors be level?

Taller modern buildings are built on concrete piles.

Modern building methods use steel or concrete piles and extend down to a second, more substantial, sand layer about 25 m. below the surface.  This supports the taller steel and glass buildings one sees along the IJ.

Inside the North-South Tunnel

A related engineering problem has been tunnel-boring for underground portions of Amsterdam’s train system.  A major north-south expansion of the train system, begun in 2002, requires a 7 km tunnel under the Central Station and the IJ.  The challenges of keeping out the water, supporting train weight and avoiding the pin cushion of pilings from existing buildings is immense.  In fact, the tunnel–designed by a German company–ran into problems in 2008 and is still not open, though the first train should run in 2017.  Here’s what happened:

On 19 June 2008, during the construction of the underground station on the Vijzelgracht, a leak in the concrete wall caused water and sand to flow into the pit. This caused tremors in the wooden piles under the houses nearby, making some houses sink 15 cm into the ground. Residents had to be evacuated. The work was stopped immediately and repairs made. Then, on 9 September 2008, construction started again. The next day, more houses sank, this time 20 cm within the hour. Cracks started to appear in the walls and windows, and doors wouldn’t budge. The row of 300-year-old houses, known as the Weavers Houses, became suddenly uninhabitable.

This is why Dutch architects and engineers lie awake in the middle of the night!

A drawing from early 1800’s Amsterdam….piles gone wrong.