40'-0" integrated length without expansion joint 

There is no absolute requirement to include expansion joints. It is up to the designer to decide between a jointless integral bridge or a conventional design with joints. In the first case, however, the abutments and piers must be designed to cope with the cyclic expansion and contraction of the deck caused by seasonal temperature changes.

Regarding buildings: there are no rules in the Eurocodes. A quite common "rule of thumb" is to have an expension gap every 30 m. - But there are many buildings, where this rule is exceeded.

NO exact rules, depends of structural concept, materials, boundary conditions and details. There is a lot of different practices and many recommendations. In our office practice up to 100m for bridges. Check also on internet, for example:

http://www.transport-research.info/Upload/Documents/201509/20150929_174043_16165_AGB_2003_001.pdf

http://www.vsvi-mv.de/fileadmin/Medienpool/Seminarunterlagen/Seminare_2013/Vortrag_4_Integrale_Bauweise_DEGES.pdf

Based on our experimental research. I would recommend to use a gap large enough to prevent pounding or to use a zero gap distance. Please refer to 

Jankowski R., Seleemah A., El-Khoriby S., and Elwardany H. "Experimental Study on Pounding between Structures During Damaging Earthquakes" Advances in Fracture and Damage Mechanics XIII, Key Engineering Materials, Vol. 627, (2015) PP 249-252.

El-Khoriby S., Seleemah A., Jankowski R., and Elwardany H. "Experimental and Numerical Study on Pounding of Structures in Series",  Advances in Structural Engineering, Springer; Book ISBN: 978-81-322-2192-0; 2015.

For buildings : The width of gap for expansion joint depend upon some parameters like (span, difference between maximum and minimum ambient temperature ..etc.

It is recommended to provide the expansion joint after each (25-30) meters, and also the minimum width of gap of expansion joint taken as 25 mm.

For Bridges: we recommend that the spacing between expansion joints be at the end of girders ( over piers), and the width of the gape of expansion be equal 50mm.

Agreed with Joaquin on bridges.

Agreed with Abduljalil on buildings, but it is possible to have a jointless building.  This requires careful construction planning and timing, e.g. for a 70m jointless floor slab we will cast 30m of prestressed floor on either side, leaving a 10m middle section that will be cast later after creep has taken place (creep due to concrete curing and prestressing).

Agreed with Joaquin on bridges.

Agreed with Abduljalil on buildings, but it is possible to have a jointless building.  This requires careful construction planning and timing, e.g. for a 70m jointless floor slab we will cast 30m of prestressed floor on either side, leaving a 10m middle section that will be cast later after creep has taken place (creep due to concrete curing and prestressing).

It depends of the weather of the locality, the type of concrete used, the curing speed of the concrete. Skrinkage is the determination for the expansion joint. You may experience surface cracks and affects the strengh of the slab. If you have enough reinforcement, it may assist in the situation also.

If you will design taking the temperature effect  into consideration, then you can use a long segment. Otherwise, the maximum length of a segment will depend on the range of expected change of temperature.

For bridges based on your span length, you calculate the width of the expansion joint to be provided with a simple formula available in any text book.

For buildings it is around 20 to 30 m.

For bridges, the gap depends on the type of the bridge (steel or concrete) and on the span length. However, it can be calculated based on the temperature change and the shrinkage of concrete.

For reinforced concrete buildings,it is up to 100 feet (35 m).

For Bridges, as others said, there is no limitation. if your designing simply supported span just an expansion joints on piers and abutments are sufficient. But you may considering continuous bridge ,then 3-span +expansion joint is common.

Theoretically, expansion gap can be provided after any length provided you set the gap wide enough to accommodate the expansion of that length due maximum temperature difference. Usually, for simple bridges expansion gaps are placed over the pier heads for every span. For continuous bridge (as pointed out by others) gaps are set every 4th span (say at about 100 to 300m). For, RC buildings expansion gaps of about 50mm are provided after every 100m. But, many advocate for larger spacing such as 200m.

The longest continuous bridge between expansion joints is about 2.5km. For a concrete bridge I have designed and built 1750m long structure, see Collings D (2001) The A13 viaduct: construction of a large monolithic concrete bridge deck (link below). Typically 300m to 500m is more economic in bearing and joint costs.

http://www.icevirtuallibrary.com/doi/full/10.1680/stbu.2001.146.1.85

For bridges, the girders are normally simply supported; therefore movement due to weather is not a design issue.  However, if there exists a large gap, vehiular load will generate very high level of impact - especially if the bridge allows 80 - 100km/h traffic.

In buildings, the movement joints are provided for many reasons: (1) to resist dishing-doming of footing in shrink-swell soil. (2) thermal expansion/ contraction of building materials exposed to weather and (3) natural growth or shrinkage of the material (such as clay brick or concrete blocks).  For designing an appropriate gap size, one has to allow for 30 (or 50) year characteristic coefficient of expansion of the material/ soil properties/ water table/ average high and low temperature.

The consideration may depend on both the local temperature range and the overall lenght of the building for a long building beyond 30 or 35 m it could be considered after each 35 m spacing in buildings and the width could be between 25 mm to 50 mm ideally I think 38 mm may be appropriate.

Expansion joints in R.C. buildings depends on many factors such as:

1- Seasonal and daily temperature gradient,

2- Outside and inside thermal insulation, and

3- Type of structure, bearing walls system, reinforced concrete frames.

However, the current practice is to provide a gap of 25 to 40 mm at each 35 m.

In bridges, it depends whether it is simply supported spans isolated from each other, in this case a gap of 25 to 35 mm is sufficient. If it is continuous, joints must be provided every three continuous spans.   

In beam-column or slab-column framed buildings, 30-35m appears to be adequate, even if conservative. The National Academy of Sciences, Washington DC, in its Technical Report No.65 (Expansion Joints in Buildings), recommended an empirical approach that can be used, based on a graphical relationship between allowable building length (without joint) and design temperature change.