if 2 human body cells joined, how many chromosomes would be in the newly formed offspring cell?

I assume you mean diploid cells. well that raises a problem because now you have 92 chromosomes (46 pairs). In normal reproduction, haploid cells only have half of the chromosomes each, so when egg and sperm meet they pair up again and that gives you the full set of 46 chromosomes arranged in 23 pairs.
if you are combining diploid cells then every time you reproduce you are doubling the number of chromosomes that's going to cause a lot of abnormalities and pretty quickly it would get to the point where it's not viable at all.

there would be 46 chromosomes

Human somatic cells have 46 chromosomes - 23 pairs.

The combination of somatic cells into one would mean 92 chromosomes, 23 quadruplets.

Since the duplication of any single chromosome leads to major malformations and/or disorders (klienfelter's syndrome, down's sydrome), the duplication of the entire genome would be catastrophic, leading to spontaneous abortion.

There are some, very few, people that survive past birth with one extra set of chromosomes, or triploidy, but rarely much further unless they are only partially triploid.

Depends on the cells. If the cells were haploid sex cells, there would be 46 choromosomes. This happens regularly in fertilization and develops a normal fetus.
In somatic cells, there would be 92 chromosomes. The cell would be inviable.